Project Euler - Githubissues

[ ] Problem 1: Multiples of 3 and 5
[ ] Problem 2: Even Fibonacci Numbers
[ ] Problem 3: Largest prime factor
[ ] Problem 4: Largest palindrome product
[ ] Problem 5: Smallest multiple
[ ] Problem 6: Sum square difference
[ ] Problem 7: 10001st prime
[ ] Problem 8: Largest product in a series
[ ] Problem 9: Special Pythagorean triplet
[ ] Problem 10: Summation of primes
[ ] Problem 11: Largest product in a grid
[ ] Problem 12: Highly divisible triangular number
[ ] Problem 13: Large sum
[ ] Problem 14: Longest Collatz sequence
[ ] Problem 15: Lattice paths
[ ] Problem 16: Power digit sum
[ ] Problem 17: Number letter counts
[ ] Problem 18: Maximum path sum I
[ ] Problem 19: Counting Sundays
[ ] Problem 20: Factorial digit sum
[ ] Problem 21: Amicable numbers
[ ] Problem 22: Names scores
[ ] Problem 23: Non-abundant sums
[ ] Problem 24: Lexicographic permutations
[ ] Problem 25: 1000-digit Fibonacci number
[ ] Problem 26: Reciprocal cycles
[ ] Problem 27: Quadratic primes
[ ] Problem 28: Number spiral diagonals
[ ] Problem 29: Distinct powers
[ ] Problem 30: Digit n powers
[ ] Problem 31: Coin sums
[ ] Problem 32: Pandigital products
[ ] Problem 33: Digit cancelling fractions
[ ] Problem 34: Digit factorials
[ ] Problem 35: Circular primes
[ ] Problem 36: Double-base palindromes
[ ] Problem 37: Truncatable primes
[ ] Problem 38: Pandigital multiples
[ ] Problem 39: Integer right triangles
[ ] Problem 40: Champernowne's constant
[ ] Problem 41: Pandigital prime
[ ] Problem 42: Coded triangle numbers
[ ] Problem 43: Sub-string divisibility
[ ] Problem 44: Pentagon numbers
[ ] Problem 45: Triangular, pentagonal, and hexagonal
[ ] Problem 46: Goldbach's other conjecture
[ ] Problem 47: Distinct primes factors
[ ] Problem 48: Self powers
[ ] Problem 49: Prime permutations
[ ] Problem 50: Consecutive prime sum
[ ] Problem 51: Prime digit replacements
[ ] Problem 52: Permuted multiples
[ ] Problem 53: Combinatoric selections
[ ] Problem 54: Poker hands
[ ] Problem 55: Lychrel numbers
[ ] Problem 56: Powerful digit sum
[ ] Problem 57: Square root convergents
[ ] Problem 58: Spiral primes
[ ] Problem 59: XOR decryption
[ ] Problem 60: Prime pair sets
[ ] Problem 61: Cyclical figurate numbers
[ ] Problem 62: Cubic permutations
[ ] Problem 63: Powerful digit counts
[ ] Problem 64: Odd period square roots
[ ] Problem 65: Convergents of e
[ ] Problem 66: Diophantine equation
[ ] Problem 67: Maximum path sum II
[ ] Problem 68: Magic 5-gon ring
[ ] Problem 69: Totient maximum
[ ] Problem 70: Totient permutation
[ ] Problem 71: Ordered fractions
[ ] Problem 72: Counting fractions
[ ] Problem 73: Counting fractions in a range
[ ] Problem 74: Digit factorial chains
[ ] Problem 75: Singular integer right triangles
[ ] Problem 76: Counting summations
[ ] Problem 77: Prime summations
[ ] Problem 78: Coin partitions
[ ] Problem 79: Passcode derivation
[ ] Problem 80: Square root digital expansion
[ ] Problem 81: Path sum: two ways
[ ] Problem 82: Path sum: three ways
[ ] Problem 83: Path sum: four ways
[ ] Problem 84: Monopoly odds
[ ] Problem 85: Counting rectangles
[ ] Problem 86: Cuboid route
[ ] Problem 87: Prime power triples
[ ] Problem 88: Product-sum numbers
[ ] Problem 89: Roman numerals
[ ] Problem 90: Cube digit pairs
[ ] Problem 91: Right triangles with integer coordinates
[ ] Problem 92: Square digit chains
[ ] Problem 93: Arithmetic expressions
[ ] Problem 94: Almost equilateral triangles
[ ] Problem 95: Amicable chains
[ ] Problem 96: Su Doku
[ ] Problem 97: Large non-Mersenne prime
[ ] Problem 98: Anagramic squares
[ ] Problem 99: Largest exponential
[ ] Problem 100: Arranged probability
[ ] Problem 101: Optimum polynomial
[ ] Problem 102: Triangle containment
[ ] Problem 103: Special subset sums: optimum
[ ] Problem 104: Pandigital Fibonacci ends
[ ] Problem 105: Special subset sums: testing
[ ] Problem 106: Special subset sums: meta-testing
[ ] Problem 107: Minimal network
[ ] Problem 108: Diophantine Reciprocals I
[ ] Problem 109: Darts
[ ] Problem 110: Diophantine Reciprocals II
[ ] Problem 111: Primes with runs
[ ] Problem 112: Bouncy numbers
[ ] Problem 113: Non-bouncy numbers
[ ] Problem 114: Counting block combinations I
[ ] Problem 115: Counting block combinations II
[ ] Problem 116: Red, green or blue tiles
[ ] Problem 117: Red, green, and blue tiles
[ ] Problem 118: Pandigital prime sets
[ ] Problem 119: Digit power sum
[ ] Problem 120: Square remainders
[ ] Problem 121: Disc game prize fund
[ ] Problem 122: Efficient exponentiation
[ ] Problem 123: Prime square remainders
[ ] Problem 124: Ordered radicals
[ ] Problem 125: Palindromic sums
[ ] Problem 126: Cuboid layers
[ ] Problem 127: abc-hits
[ ] Problem 128: Hexagonal tile differences
[ ] Problem 129: Repunit divisibility
[ ] Problem 130: Composites with prime repunit property
[ ] Problem 131: Prime cube partnership
[ ] Problem 132: Large repunit factors
[ ] Problem 133: Repunit nonfactors
[ ] Problem 134: Prime pair connection
[ ] Problem 135: Same differences
[ ] Problem 136: Singleton difference
[ ] Problem 137: Fibonacci golden nuggets
[ ] Problem 138: Special isosceles triangles
[ ] Problem 139: Pythagorean tiles
[ ] Problem 140: Modified Fibonacci golden nuggets
[ ] Problem 141: Investigating progressive numbers, n, which are also square
[ ] Problem 142: Perfect Square Collection
[ ] Problem 143: Investigating the Torricelli point of a triangle
[ ] Problem 144: Investigating multiple reflections of a laser beam
[ ] Problem 145: How many reversible numbers are there below one-billion?
[ ] Problem 146: Investigating a Prime Pattern
[ ] Problem 147: Rectangles in cross-hatched grids
[ ] Problem 148: Exploring Pascal's triangle
[ ] Problem 149: Searching for a maximum-sum subsequence
[ ] Problem 150: Searching a triangular array for a sub-triangle having minimum-sum
[ ] Problem 151: Paper sheets of standard sizes: an expected-value problem
[ ] Problem 152: Writing 1/2 as a sum of inverse squares
[ ] Problem 153: Investigating Gaussian Integers
[ ] Problem 154: Exploring Pascal's pyramid
[ ] Problem 155: Counting Capacitor Circuits
[ ] Problem 156: Counting Digits
[ ] Problem 157: Solving the diophantine equation 1/a+1/b= p/10n
[ ] Problem 158: Exploring strings for which only one character comes lexicographically after its neighbour to the left
[ ] Problem 159: Digital root sums of factorisations
[ ] Problem 160: Factorial trailing digits
[ ] Problem 161: Triominoes
[ ] Problem 162: Hexadecimal numbers
[ ] Problem 163: Cross-hatched triangles
[ ] Problem 164: Numbers for which no three consecutive digits have a sum greater than a given value
[ ] Problem 165: Intersections
[ ] Problem 166: Criss Cross
[ ] Problem 167: Investigating Ulam sequences
[ ] Problem 168: Number Rotations
[ ] Problem 169: Exploring the number of different ways a number can be expressed as a sum of powers of 2
[ ] Problem 170: Find the largest 0 to 9 pandigital that can be formed by concatenating products
[ ] Problem 171: Finding numbers for which the sum of the squares of the digits is a square
[ ] Problem 172: Investigating numbers with few repeated digits
[ ] Problem 173: Using up to one million tiles how many different "hollow" square laminae can be formed?
[ ] Problem 174: Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements
[ ] Problem 175: Fractions involving the number of different ways a number can be expressed as a sum of powers of 2
[ ] Problem 176: Right-angled triangles that share a cathetus
[ ] Problem 177: Integer angled Quadrilaterals
[ ] Problem 178: Step Numbers
[ ] Problem 179: Consecutive positive divisors
[ ] Problem 180: Rational zeros of a function of three variables
[ ] Problem 181: Investigating in how many ways objects of two different colours can be grouped
[ ] Problem 182: RSA encryption
[ ] Problem 183: Maximum product of parts
[ ] Problem 184: Triangles containing the origin
[ ] Problem 185: Number Mind
[ ] Problem 186: Connectedness of a network
[ ] Problem 187: Semiprimes
[ ] Problem 188: The hyperexponentiation of a number
[ ] Problem 189: Tri-colouring a triangular grid
[ ] Problem 190: Maximising a weighted product
[ ] Problem 191: Prize Strings
[ ] Problem 192: Best Approximations
[ ] Problem 193: Squarefree Numbers
[ ] Problem 194: Coloured Configurations
[ ] Problem 195: Inscribed circles of triangles with one angle of 60 degrees
[ ] Problem 196: Prime triplets
[ ] Problem 197: Investigating the behaviour of a recursively defined sequence
[ ] Problem 198: Ambiguous Numbers
[ ] Problem 199: Iterative Circle Packing
[ ] Problem 200: Find the 200th prime-proof sqube containing the contiguous sub-string "200"
[ ] Problem 201: Subsets with a unique sum
[ ] Problem 202: Laserbeam
[ ] Problem 203: Squarefree Binomial Coefficients
[ ] Problem 204: Generalised Hamming Numbers
[ ] Problem 205: Dice Game
[ ] Problem 206: Concealed Square
[ ] Problem 207: Integer partition equations
[ ] Problem 208: Robot Walks
[ ] Problem 209: Circular Logic
[ ] Problem 210: Obtuse Angled Triangles
[ ] Problem 211: Divisor Square Sum
[ ] Problem 212: Combined Volume of Cuboids
[ ] Problem 213: Flea Circus
[ ] Problem 214: Totient Chains
[ ] Problem 215: Crack-free Walls
[ ] Problem 216: Investigating the primality of numbers of the form 2n2-1
[ ] Problem 217: Balanced Numbers
[ ] Problem 218: Perfect right-angled triangles
[ ] Problem 219: Skew-cost coding
[ ] Problem 220: Heighway Dragon
[ ] Problem 221: Alexandrian Integers
[ ] Problem 222: Sphere Packing
[ ] Problem 223: Almost right-angled triangles I
[ ] Problem 224: Almost right-angled triangles II
[ ] Problem 225: Tribonacci non-divisors
[ ] Problem 226: A Scoop of Blancmange
[ ] Problem 227: The Chase
[ ] Problem 228: Minkowski Sums
[ ] Problem 229: Four Representations using Squares
[ ] Problem 230: Fibonacci Words
[ ] Problem 231: The prime factorisation of binomial coefficients
[ ] Problem 232: The Race
[ ] Problem 233: Lattice points on a circle
[ ] Problem 234: Semidivisible numbers
[ ] Problem 235: An Arithmetic Geometric sequence
[ ] Problem 236: Luxury Hampers
[ ] Problem 237: Tours on a 4 x n playing board
[ ] Problem 238: Infinite string tour
[ ] Problem 239: Twenty-two Foolish Primes
[ ] Problem 240: Top Dice
[ ] Problem 241: Perfection Quotients
[ ] Problem 242: Odd Triplets
[ ] Problem 243: Resilience
[ ] Problem 244: Sliders
[ ] Problem 245: Coresilience
[ ] Problem 246: Tangents to an ellipse
[ ] Problem 247: Squares under a hyperbola
[ ] Problem 248: Numbers for which Euler’s totient function equals 13!
[ ] Problem 249: Prime Subset Sums
[ ] Problem 250: 250250
[ ] Problem 251: Cardano Triplets
[ ] Problem 252: Convex Holes
[ ] Problem 253: Tidying up
[ ] Problem 254: Sums of Digit Factorials
[ ] Problem 255: Rounded Square Roots
[ ] Problem 256: Tatami-Free Rooms
[ ] Problem 257: Angular Bisectors
[ ] Problem 258: A lagged Fibonacci sequence
[ ] Problem 259: Reachable Numbers
[ ] Problem 260: Stone Game
[ ] Problem 261: Pivotal Square Sums
[ ] Problem 262: Mountain Range
[ ] Problem 263: An engineers' dream come true
[ ] Problem 264: Triangle Centres
[ ] Problem 265: Binary Circles
[ ] Problem 266: Pseudo Square Root
[ ] Problem 267: Billionaire
[ ] Problem 268: Counting numbers with at least four distinct prime factors less than 100
[ ] Problem 269: Polynomials with at least one integer root
[ ] Problem 270: Cutting Squares
[ ] Problem 271: Modular Cubes, part 1
[ ] Problem 272: Modular Cubes, part 2
[ ] Problem 273: Sum of Squares
[ ] Problem 274: Divisibility Multipliers
[ ] Problem 275: Balanced Sculptures
[ ] Problem 276: Primitive Triangles
[ ] Problem 277: A Modified Collatz sequence
[ ] Problem 278: Linear Combinations of Semiprimes
[ ] Problem 279: Triangles with integral sides and an integral angle
[ ] Problem 280: Ant and seeds
[ ] Problem 281: Pizza Toppings
[ ] Problem 282: The Ackermann function
[ ] Problem 283: Integer sided triangles for which the area/perimeter ratio is integral
[ ] Problem 284: Steady Squares
[ ] Problem 285: Pythagorean odds
[ ] Problem 286: Scoring probabilities
[ ] Problem 287: Quadtree encoding (a simple compression algorithm)
[ ] Problem 288: An enormous factorial
[ ] Problem 289: Eulerian Cycles
[ ] Problem 290: Digital Signature
[ ] Problem 291: Panaitopol Primes
[ ] Problem 292: Pythagorean Polygons
[ ] Problem 293: Pseudo-Fortunate Numbers
[ ] Problem 294: Sum of digits - experience #23
[ ] Problem 295: Lenticular holes
[ ] Problem 296: Angular Bisector and Tangent
[ ] Problem 297: Zeckendorf Representation
[ ] Problem 298: Selective Amnesia
[ ] Problem 299: Three similar triangles
[ ] Problem 300: Protein folding
[ ] Problem 301: Nim
[ ] Problem 302: Strong Achilles Numbers
[ ] Problem 303: Multiples with small digits
[ ] Problem 304: Primonacci
[ ] Problem 305: Reflexive Position
[ ] Problem 306: Paper-strip Game
[ ] Problem 307: Chip Defects
[ ] Problem 308: An amazing Prime-generating Automaton
[ ] Problem 309: Integer Ladders
[ ] Problem 310: Nim Square
[ ] Problem 311: Biclinic Integral Quadrilaterals
[ ] Problem 312: Cyclic paths on Sierpiński graphs
[ ] Problem 313: Sliding game
[ ] Problem 314: The Mouse on the Moon
[ ] Problem 315: Digital root clocks
[ ] Problem 316: Numbers in decimal expansions
[ ] Problem 317: Firecracker
[ ] Problem 318: 2011 nines
[ ] Problem 319: Bounded Sequences
[ ] Problem 320: Factorials divisible by a huge integer
[ ] Problem 321: Swapping Counters
[ ] Problem 322: Binomial coefficients divisible by 10
[ ] Problem 323: Bitwise-OR operations on random integers
[ ] Problem 324: Building a tower
[ ] Problem 325: Stone Game II
[ ] Problem 326: Modulo Summations
[ ] Problem 327: Rooms of Doom
[ ] Problem 328: Lowest-cost Search
[ ] Problem 329: Prime Frog
[ ] Problem 330: Euler's Number
[ ] Problem 331: Cross flips
[ ] Problem 332: Spherical triangles
[ ] Problem 333: Special partitions
[ ] Problem 334: Spilling the beans
[ ] Problem 335: Gathering the beans
[ ] Problem 336: Maximix Arrangements
[ ] Problem 337: Totient Stairstep Sequences
[ ] Problem 338: Cutting Rectangular Grid Paper
[ ] Problem 339: Peredur fab Efrawg
[ ] Problem 340: Crazy Function
[ ] Problem 341: Golomb's self-describing sequence
[ ] Problem 342: The totient of a square is a cube
[ ] Problem 343: Fractional Sequences
[ ] Problem 344: Silver dollar game
[ ] Problem 345: Matrix Sum
[ ] Problem 346: Strong Repunits
[ ] Problem 347: Largest integer divisible by two primes
[ ] Problem 348: Sum of a square and a cube
[ ] Problem 349: Langton's ant
[ ] Problem 350: Constraining the least greatest and the greatest least
[ ] Problem 351: Hexagonal orchards
[ ] Problem 352: Blood tests
[ ] Problem 353: Risky moon
[ ] Problem 354: Distances in a bee's honeycomb
[ ] Problem 355: Maximal coprime subset
[ ] Problem 356: Largest roots of cubic polynomials
[ ] Problem 357: Prime generating integers
[ ] Problem 358: Cyclic numbers
[ ] Problem 359: Hilbert's New Hotel
[ ] Problem 360: Scary Sphere
[ ] Problem 361: Subsequence of Thue-Morse sequence
[ ] Problem 362: Squarefree factors
[ ] Problem 363: Bézier Curves
[ ] Problem 364: Comfortable distance
[ ] Problem 365: A huge binomial coefficient
[ ] Problem 366: Stone Game III
[ ] Problem 367: Bozo sort
[ ] Problem 368: A Kempner-like series
[ ] Problem 369: Badugi
[ ] Problem 370: Geometric triangles
[ ] Problem 371: Licence plates
[ ] Problem 372: Pencils of rays
[ ] Problem 373: Circumscribed Circles
[ ] Problem 374: Maximum Integer Partition Product
[ ] Problem 375: Minimum of subsequences
[ ] Problem 376: Nontransitive sets of dice
[ ] Problem 377: Sum of digits, experience 13
[ ] Problem 378: Triangle Triples
[ ] Problem 379: Least common multiple count
[ ] Problem 380: Amazing Mazes!
[ ] Problem 381: (prime-k) factorial
[ ] Problem 382: Generating polygons
[ ] Problem 383: Divisibility comparison between factorials
[ ] Problem 384: Rudin-Shapiro sequence
[ ] Problem 385: Ellipses inside triangles
[ ] Problem 386: Maximum length of an antichain
[ ] Problem 387: Harshad Numbers
[ ] Problem 388: Distinct Lines
[ ] Problem 389: Platonic Dice
[ ] Problem 390: Triangles with non rational sides and integral area
[ ] Problem 391: Hopping Game
[ ] Problem 392: Enmeshed unit circle
[ ] Problem 393: Migrating ants
[ ] Problem 394: Eating pie
[ ] Problem 395: Pythagorean tree
[ ] Problem 396: Weak Goodstein sequence
[ ] Problem 397: Triangle on parabola
[ ] Problem 398: Cutting rope
[ ] Problem 399: Squarefree Fibonacci Numbers
[ ] Problem 400: Fibonacci tree game
[ ] Problem 401: Sum of squares of divisors
[ ] Problem 402: Integer-valued polynomials
[ ] Problem 403: Lattice points enclosed by parabola and line
[ ] Problem 404: Crisscross Ellipses
[ ] Problem 405: A rectangular tiling
[ ] Problem 406: Guessing Game
[ ] Problem 407: Idempotents
[ ] Problem 408: Admissible paths through a grid
[ ] Problem 409: Nim Extreme
[ ] Problem 410: Circle and tangent line
[ ] Problem 411: Uphill paths
[ ] Problem 412: Gnomon numbering
[ ] Problem 413: One-child Numbers
[ ] Problem 414: Kaprekar constant
[ ] Problem 415: Titanic sets
[ ] Problem 416: A frog's trip
[ ] Problem 417: Reciprocal cycles II
[ ] Problem 418: Factorisation triples
[ ] Problem 419: Look and say sequence
[ ] Problem 420: 2x2 positive integer matrix
[ ] Problem 421: Prime factors of n15+1
[ ] Problem 422: Sequence of points on a hyperbola
[ ] Problem 423: Consecutive die throws
[ ] Problem 424: Kakuro
[ ] Problem 425: Prime connection
[ ] Problem 426: Box-ball system
[ ] Problem 427: n-sequences
[ ] Problem 428: Necklace of Circles
[ ] Problem 429: Sum of squares of unitary divisors
[ ] Problem 430: Range flips
[ ] Problem 431: Square Space Silo
[ ] Problem 432: Totient sum
[ ] Problem 433: Steps in Euclid's algorithm
[ ] Problem 434: Rigid graphs
[ ] Problem 435: Polynomials of Fibonacci numbers
[ ] Problem 436: Unfair wager
[ ] Problem 437: Fibonacci primitive roots
[ ] Problem 438: Integer part of polynomial equation's solutions
[ ] Problem 439: Sum of sum of divisors
[ ] Problem 440: GCD and Tiling
[ ] Problem 441: The inverse summation of coprime couples
[ ] Problem 442: Eleven-free integers
[ ] Problem 443: GCD sequence
[ ] Problem 444: The Roundtable Lottery
[ ] Problem 445: Retractions A
[ ] Problem 446: Retractions B
[ ] Problem 447: Retractions C
[ ] Problem 448: Average least common multiple
[ ] Problem 449: Chocolate covered candy
[ ] Problem 450: Hypocycloid and Lattice points
[ ] Problem 451: Modular inverses
[ ] Problem 452: Long Products
[ ] Problem 453: Lattice Quadrilaterals
[ ] Problem 454: Diophantine reciprocals III
[ ] Problem 455: Powers With Trailing Digits
[ ] Problem 456: Triangles containing the origin II
[ ] Problem 457: A polynomial modulo the square of a prime
[ ] Problem 458: Permutations of Project
[ ] Problem 459: Flipping game
[ ] Problem 460: An ant on the move
[ ] Problem 461: Almost Pi
[ ] Problem 462: Permutation of 3-smooth numbers
[ ] Problem 463: A weird recurrence relation
[ ] Problem 464: Möbius function and intervals
[ ] Problem 465: Polar polygons
[ ] Problem 466: Distinct terms in a multiplication table
[ ] Problem 467: Superinteger
[ ] Problem 468: Smooth divisors of binomial coefficients
[ ] Problem 469: Empty chairs
[ ] Problem 470: Super Ramvok
[ ] Problem 471: Triangle inscribed in ellipse
[ ] Problem 472: Comfortable Distance II
[ ] Problem 473: Phigital number base
[ ] Problem 474: Last digits of divisors
[ ] Problem 475: Music festival
[ ] Problem 476: Circle Packing II
[ ] Problem 477: Number Sequence Game
[ ] Problem 478: Mixtures
[ ] Problem 479: Roots on the Rise
[ ] Problem 480: The Last Question

[ ] Problem 1: Multiples of 3 and 5

[ ] Problem 2: Even Fibonacci Numbers

[ ] Problem 3: Largest prime factor

[ ] Problem 4: Largest palindrome product

[ ] Problem 5: Smallest multiple

[ ] Problem 6: Sum square difference

[ ] Problem 7: 10001st prime

[ ] Problem 8: Largest product in a series

[ ] Problem 9: Special Pythagorean triplet

[ ] Problem 10: Summation of primes

[ ] Problem 11: Largest product in a grid

[ ] Problem 12: Highly divisible triangular number

[ ] Problem 13: Large sum

[ ] Problem 14: Longest Collatz sequence

[ ] Problem 15: Lattice paths

[ ] Problem 16: Power digit sum

[ ] Problem 17: Number letter counts

[ ] Problem 18: Maximum path sum I

[ ] Problem 19: Counting Sundays

[ ] Problem 20: Factorial digit sum

[ ] Problem 21: Amicable numbers

[ ] Problem 22: Names scores

[ ] Problem 23: Non-abundant sums

[ ] Problem 24: Lexicographic permutations

[ ] Problem 25: 1000-digit Fibonacci number

[ ] Problem 26: Reciprocal cycles

[ ] Problem 27: Quadratic primes

[ ] Problem 28: Number spiral diagonals

[ ] Problem 29: Distinct powers

[ ] Problem 30: Digit n powers

[ ] Problem 31: Coin sums

[ ] Problem 32: Pandigital products

[ ] Problem 33: Digit cancelling fractions

[ ] Problem 34: Digit factorials

[ ] Problem 35: Circular primes

[ ] Problem 36: Double-base palindromes

[ ] Problem 37: Truncatable primes

[ ] Problem 38: Pandigital multiples

[ ] Problem 39: Integer right triangles

[ ] Problem 40: Champernowne's constant

[ ] Problem 41: Pandigital prime

[ ] Problem 42: Coded triangle numbers

[ ] Problem 43: Sub-string divisibility

[ ] Problem 44: Pentagon numbers

[ ] Problem 45: Triangular, pentagonal, and hexagonal

[ ] Problem 46: Goldbach's other conjecture

[ ] Problem 47: Distinct primes factors

[ ] Problem 48: Self powers

[ ] Problem 49: Prime permutations

[ ] Problem 50: Consecutive prime sum

[ ] Problem 51: Prime digit replacements

[ ] Problem 52: Permuted multiples

[ ] Problem 53: Combinatoric selections

[ ] Problem 54: Poker hands

[ ] Problem 55: Lychrel numbers

[ ] Problem 56: Powerful digit sum

[ ] Problem 57: Square root convergents

[ ] Problem 58: Spiral primes

[ ] Problem 59: XOR decryption

[ ] Problem 60: Prime pair sets

[ ] Problem 61: Cyclical figurate numbers

[ ] Problem 62: Cubic permutations

[ ] Problem 63: Powerful digit counts

[ ] Problem 64: Odd period square roots

[ ] Problem 65: Convergents of e

[ ] Problem 66: Diophantine equation

[ ] Problem 67: Maximum path sum II

[ ] Problem 68: Magic 5-gon ring

[ ] Problem 69: Totient maximum

[ ] Problem 70: Totient permutation

[ ] Problem 71: Ordered fractions

[ ] Problem 72: Counting fractions

[ ] Problem 73: Counting fractions in a range

[ ] Problem 74: Digit factorial chains

[ ] Problem 75: Singular integer right triangles

[ ] Problem 76: Counting summations

[ ] Problem 77: Prime summations

[ ] Problem 78: Coin partitions

[ ] Problem 79: Passcode derivation

[ ] Problem 80: Square root digital expansion

[ ] Problem 81: Path sum: two ways

[ ] Problem 82: Path sum: three ways

[ ] Problem 83: Path sum: four ways

[ ] Problem 84: Monopoly odds

[ ] Problem 85: Counting rectangles

[ ] Problem 86: Cuboid route

[ ] Problem 87: Prime power triples

[ ] Problem 88: Product-sum numbers

[ ] Problem 89: Roman numerals

[ ] Problem 90: Cube digit pairs

[ ] Problem 91: Right triangles with integer coordinates

[ ] Problem 92: Square digit chains

[ ] Problem 93: Arithmetic expressions

[ ] Problem 94: Almost equilateral triangles

[ ] Problem 95: Amicable chains

[ ] Problem 96: Su Doku

[ ] Problem 97: Large non-Mersenne prime

[ ] Problem 98: Anagramic squares

[ ] Problem 99: Largest exponential

[ ] Problem 100: Arranged probability

[ ] Problem 101: Optimum polynomial

[ ] Problem 102: Triangle containment

[ ] Problem 103: Special subset sums: optimum

[ ] Problem 104: Pandigital Fibonacci ends

[ ] Problem 105: Special subset sums: testing

[ ] Problem 106: Special subset sums: meta-testing

[ ] Problem 107: Minimal network

[ ] Problem 108: Diophantine Reciprocals I

[ ] Problem 109: Darts

[ ] Problem 110: Diophantine Reciprocals II

[ ] Problem 111: Primes with runs

[ ] Problem 112: Bouncy numbers

[ ] Problem 113: Non-bouncy numbers

[ ] Problem 114: Counting block combinations I

[ ] Problem 115: Counting block combinations II

[ ] Problem 116: Red, green or blue tiles

[ ] Problem 117: Red, green, and blue tiles

[ ] Problem 118: Pandigital prime sets

[ ] Problem 119: Digit power sum

[ ] Problem 120: Square remainders

[ ] Problem 121: Disc game prize fund

[ ] Problem 122: Efficient exponentiation

[ ] Problem 123: Prime square remainders

[ ] Problem 124: Ordered radicals

[ ] Problem 125: Palindromic sums

[ ] Problem 126: Cuboid layers

[ ] Problem 127: abc-hits

[ ] Problem 128: Hexagonal tile differences

[ ] Problem 129: Repunit divisibility

[ ] Problem 130: Composites with prime repunit property

[ ] Problem 131: Prime cube partnership

[ ] Problem 132: Large repunit factors

[ ] Problem 133: Repunit nonfactors

[ ] Problem 134: Prime pair connection

[ ] Problem 135: Same differences

[ ] Problem 136: Singleton difference

[ ] Problem 137: Fibonacci golden nuggets

[ ] Problem 138: Special isosceles triangles

[ ] Problem 139: Pythagorean tiles

[ ] Problem 140: Modified Fibonacci golden nuggets

[ ] Problem 141: Investigating progressive numbers, n, which are also square

[ ] Problem 142: Perfect Square Collection

[ ] Problem 143: Investigating the Torricelli point of a triangle

[ ] Problem 144: Investigating multiple reflections of a laser beam

[ ] Problem 145: How many reversible numbers are there below one-billion?

[ ] Problem 146: Investigating a Prime Pattern

[ ] Problem 147: Rectangles in cross-hatched grids

[ ] Problem 148: Exploring Pascal's triangle

[ ] Problem 149: Searching for a maximum-sum subsequence

[ ] Problem 150: Searching a triangular array for a sub-triangle having minimum-sum

[ ] Problem 151: Paper sheets of standard sizes: an expected-value problem

[ ] Problem 152: Writing 1/2 as a sum of inverse squares

[ ] Problem 153: Investigating Gaussian Integers

[ ] Problem 154: Exploring Pascal's pyramid

[ ] Problem 155: Counting Capacitor Circuits

[ ] Problem 156: Counting Digits

[ ] Problem 157: Solving the diophantine equation 1/a+1/b= p/10n

[ ] Problem 158: Exploring strings for which only one character comes lexicographically after its neighbour to the left

[ ] Problem 159: Digital root sums of factorisations

[ ] Problem 160: Factorial trailing digits

[ ] Problem 161: Triominoes

[ ] Problem 162: Hexadecimal numbers

[ ] Problem 163: Cross-hatched triangles

[ ] Problem 164: Numbers for which no three consecutive digits have a sum greater than a given value

[ ] Problem 165: Intersections

[ ] Problem 166: Criss Cross

[ ] Problem 167: Investigating Ulam sequences

[ ] Problem 168: Number Rotations

[ ] Problem 169: Exploring the number of different ways a number can be expressed as a sum of powers of 2

[ ] Problem 170: Find the largest 0 to 9 pandigital that can be formed by concatenating products

[ ] Problem 171: Finding numbers for which the sum of the squares of the digits is a square

[ ] Problem 172: Investigating numbers with few repeated digits

[ ] Problem 173: Using up to one million tiles how many different "hollow" square laminae can be formed?

[ ] Problem 174: Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements

[ ] Problem 175: Fractions involving the number of different ways a number can be expressed as a sum of powers of 2

[ ] Problem 176: Right-angled triangles that share a cathetus

[ ] Problem 177: Integer angled Quadrilaterals

[ ] Problem 178: Step Numbers

[ ] Problem 179: Consecutive positive divisors

[ ] Problem 180: Rational zeros of a function of three variables

[ ] Problem 181: Investigating in how many ways objects of two different colours can be grouped

[ ] Problem 182: RSA encryption

[ ] Problem 183: Maximum product of parts

[ ] Problem 184: Triangles containing the origin

[ ] Problem 185: Number Mind

[ ] Problem 186: Connectedness of a network

[ ] Problem 187: Semiprimes

[ ] Problem 188: The hyperexponentiation of a number

[ ] Problem 189: Tri-colouring a triangular grid

[ ] Problem 190: Maximising a weighted product

[ ] Problem 191: Prize Strings

[ ] Problem 192: Best Approximations

[ ] Problem 193: Squarefree Numbers

[ ] Problem 194: Coloured Configurations

[ ] Problem 195: Inscribed circles of triangles with one angle of 60 degrees

[ ] Problem 196: Prime triplets

[ ] Problem 197: Investigating the behaviour of a recursively defined sequence

[ ] Problem 198: Ambiguous Numbers

[ ] Problem 199: Iterative Circle Packing

[ ] Problem 200: Find the 200th prime-proof sqube containing the contiguous sub-string "200"

[ ] Problem 201: Subsets with a unique sum

[ ] Problem 202: Laserbeam

[ ] Problem 203: Squarefree Binomial Coefficients

[ ] Problem 204: Generalised Hamming Numbers

[ ] Problem 205: Dice Game

[ ] Problem 206: Concealed Square

[ ] Problem 207: Integer partition equations

[ ] Problem 208: Robot Walks

[ ] Problem 209: Circular Logic

[ ] Problem 210: Obtuse Angled Triangles

[ ] Problem 211: Divisor Square Sum

[ ] Problem 212: Combined Volume of Cuboids

[ ] Problem 213: Flea Circus

[ ] Problem 214: Totient Chains

[ ] Problem 215: Crack-free Walls

[ ] Problem 216: Investigating the primality of numbers of the form 2n2-1

[ ] Problem 217: Balanced Numbers

[ ] Problem 218: Perfect right-angled triangles

[ ] Problem 219: Skew-cost coding

[ ] Problem 220: Heighway Dragon

[ ] Problem 221: Alexandrian Integers

[ ] Problem 222: Sphere Packing

[ ] Problem 223: Almost right-angled triangles I

[ ] Problem 224: Almost right-angled triangles II

[ ] Problem 225: Tribonacci non-divisors

[ ] Problem 226: A Scoop of Blancmange

[ ] Problem 227: The Chase

[ ] Problem 228: Minkowski Sums

[ ] Problem 229: Four Representations using Squares

[ ] Problem 230: Fibonacci Words

[ ] Problem 231: The prime factorisation of binomial coefficients

[ ] Problem 232: The Race

[ ] Problem 233: Lattice points on a circle

[ ] Problem 234: Semidivisible numbers

[ ] Problem 235: An Arithmetic Geometric sequence

[ ] Problem 236: Luxury Hampers

[ ] Problem 237: Tours on a 4 x n playing board

[ ] Problem 238: Infinite string tour

[ ] Problem 239: Twenty-two Foolish Primes

[ ] Problem 240: Top Dice

[ ] Problem 241: Perfection Quotients

[ ] Problem 242: Odd Triplets

[ ] Problem 243: Resilience

[ ] Problem 244: Sliders

[ ] Problem 245: Coresilience

[ ] Problem 246: Tangents to an ellipse

[ ] Problem 247: Squares under a hyperbola

[ ] Problem 248: Numbers for which Euler’s totient function equals 13!

[ ] Problem 249: Prime Subset Sums

[ ] Problem 250: 250250

[ ] Problem 251: Cardano Triplets

[ ] Problem 252: Convex Holes

[ ] Problem 253: Tidying up

[ ] Problem 254: Sums of Digit Factorials

[ ] Problem 255: Rounded Square Roots

[ ] Problem 256: Tatami-Free Rooms

[ ] Problem 257: Angular Bisectors

[ ] Problem 258: A lagged Fibonacci sequence

[ ] Problem 259: Reachable Numbers

[ ] Problem 260: Stone Game

[ ] Problem 261: Pivotal Square Sums

[ ] Problem 262: Mountain Range

[ ] Problem 263: An engineers' dream come true

[ ] Problem 264: Triangle Centres

[ ] Problem 265: Binary Circles

[ ] Problem 266: Pseudo Square Root

[ ] Problem 267: Billionaire

[ ] Problem 268: Counting numbers with at least four distinct prime factors less than 100

[ ] Problem 269: Polynomials with at least one integer root

[ ] Problem 270: Cutting Squares

[ ] Problem 271: Modular Cubes, part 1

[ ] Problem 272: Modular Cubes, part 2

[ ] Problem 273: Sum of Squares

[ ] Problem 274: Divisibility Multipliers

[ ] Problem 275: Balanced Sculptures

[ ] Problem 276: Primitive Triangles

[ ] Problem 277: A Modified Collatz sequence

[ ] Problem 278: Linear Combinations of Semiprimes

[ ] Problem 279: Triangles with integral sides and an integral angle

[ ] Problem 280: Ant and seeds

[ ] Problem 281: Pizza Toppings

[ ] Problem 282: The Ackermann function

[ ] Problem 283: Integer sided triangles for which the area/perimeter ratio is integral

[ ] Problem 284: Steady Squares

[ ] Problem 285: Pythagorean odds

[ ] Problem 286: Scoring probabilities

[ ] Problem 287: Quadtree encoding (a simple compression algorithm)

[ ] Problem 288: An enormous factorial

[ ] Problem 289: Eulerian Cycles

[ ] Problem 290: Digital Signature

[ ] Problem 291: Panaitopol Primes

[ ] Problem 292: Pythagorean Polygons

[ ] Problem 293: Pseudo-Fortunate Numbers

[ ] Problem 294: Sum of digits - experience #23

[ ] Problem 295: Lenticular holes

[ ] Problem 296: Angular Bisector and Tangent

[ ] Problem 297: Zeckendorf Representation

[ ] Problem 298: Selective Amnesia

[ ] Problem 299: Three similar triangles

[ ] Problem 300: Protein folding

[ ] Problem 301: Nim

[ ] Problem 302: Strong Achilles Numbers

[ ] Problem 303: Multiples with small digits

[ ] Problem 304: Primonacci

[ ] Problem 305: Reflexive Position

[ ] Problem 306: Paper-strip Game

[ ] Problem 307: Chip Defects

[ ] Problem 308: An amazing Prime-generating Automaton

[ ] Problem 309: Integer Ladders

[ ] Problem 310: Nim Square

[ ] Problem 311: Biclinic Integral Quadrilaterals

[ ] Problem 312: Cyclic paths on Sierpiński graphs

[ ] Problem 313: Sliding game

[ ] Problem 314: The Mouse on the Moon

[ ] Problem 315: Digital root clocks

[ ] Problem 316: Numbers in decimal expansions

[ ] Problem 317: Firecracker

[ ] Problem 318: 2011 nines

[ ] Problem 319: Bounded Sequences

[ ] Problem 320: Factorials divisible by a huge integer

[ ] Problem 321: Swapping Counters

[ ] Problem 322: Binomial coefficients divisible by 10

[ ] Problem 323: Bitwise-OR operations on random integers

[ ] Problem 324: Building a tower

[ ] Problem 325: Stone Game II

[ ] Problem 326: Modulo Summations

[ ] Problem 327: Rooms of Doom

[ ] Problem 328: Lowest-cost Search

[ ] Problem 329: Prime Frog

[ ] Problem 330: Euler's Number

[ ] Problem 331: Cross flips

[ ] Problem 332: Spherical triangles

[ ] Problem 333: Special partitions

[ ] Problem 334: Spilling the beans

[ ] Problem 335: Gathering the beans

[ ] Problem 336: Maximix Arrangements

[ ] Problem 337: Totient Stairstep Sequences

[ ] Problem 338: Cutting Rectangular Grid Paper

[ ] Problem 339: Peredur fab Efrawg

[ ] Problem 340: Crazy Function

[ ] Problem 341: Golomb's self-describing sequence

[ ] Problem 342: The totient of a square is a cube

[ ] Problem 343: Fractional Sequences

[ ] Problem 344: Silver dollar game

[ ] Problem 345: Matrix Sum

[ ] Problem 346: Strong Repunits

[ ] Problem 347: Largest integer divisible by two primes

[ ] Problem 348: Sum of a square and a cube

[ ] Problem 349: Langton's ant

[ ] Problem 350: Constraining the least greatest and the greatest least

[ ] Problem 351: Hexagonal orchards

[ ] Problem 352: Blood tests

[ ] Problem 353: Risky moon

[ ] Problem 354: Distances in a bee's honeycomb

[ ] Problem 355: Maximal coprime subset

[ ] Problem 356: Largest roots of cubic polynomials

[ ] Problem 357: Prime generating integers

[ ] Problem 358: Cyclic numbers

[ ] Problem 359: Hilbert's New Hotel

[ ] Problem 360: Scary Sphere

[ ] Problem 361: Subsequence of Thue-Morse sequence

[ ] Problem 362: Squarefree factors

[ ] Problem 363: Bézier Curves

[ ] Problem 364: Comfortable distance

[ ] Problem 365: A huge binomial coefficient

[ ] Problem 366: Stone Game III

[ ] Problem 367: Bozo sort

[ ] Problem 368: A Kempner-like series

[ ] Problem 369: Badugi

[ ] Problem 370: Geometric triangles

[ ] Problem 371: Licence plates

[ ] Problem 372: Pencils of rays

[ ] Problem 373: Circumscribed Circles

[ ] Problem 374: Maximum Integer Partition Product

[ ] Problem 375: Minimum of subsequences

[ ] Problem 376: Nontransitive sets of dice

[ ] Problem 377: Sum of digits, experience 13

[ ] Problem 378: Triangle Triples

[ ] Problem 379: Least common multiple count

[ ] Problem 380: Amazing Mazes!

[ ] Problem 381: (prime-k) factorial

[ ] Problem 382: Generating polygons

[ ] Problem 383: Divisibility comparison between factorials

[ ] Problem 384: Rudin-Shapiro sequence

[ ] Problem 385: Ellipses inside triangles

[ ] Problem 386: Maximum length of an antichain

[ ] Problem 387: Harshad Numbers

[ ] Problem 388: Distinct Lines

[ ] Problem 389: Platonic Dice

[ ] Problem 390: Triangles with non rational sides and integral area

[ ] Problem 391: Hopping Game

[ ] Problem 392: Enmeshed unit circle

[ ] Problem 393: Migrating ants

[ ] Problem 394: Eating pie

[ ] Problem 395: Pythagorean tree

[ ] Problem 396: Weak Goodstein sequence

[ ] Problem 397: Triangle on parabola

[ ] Problem 398: Cutting rope

[ ] Problem 399: Squarefree Fibonacci Numbers

[ ] Problem 400: Fibonacci tree game

[ ] Problem 401: Sum of squares of divisors

[ ] Problem 402: Integer-valued polynomials

[ ] Problem 403: Lattice points enclosed by parabola and line

[ ] Problem 404: Crisscross Ellipses

[ ] Problem 405: A rectangular tiling

[ ] Problem 406: Guessing Game

[ ] Problem 407: Idempotents

[ ] Problem 408: Admissible paths through a grid

[ ] Problem 409: Nim Extreme

[ ] Problem 410: Circle and tangent line

[ ] Problem 411: Uphill paths

[ ] Problem 412: Gnomon numbering

[ ] Problem 413: One-child Numbers

[ ] Problem 414: Kaprekar constant

[ ] Problem 415: Titanic sets

[ ] Problem 416: A frog's trip

[ ] Problem 417: Reciprocal cycles II

[ ] Problem 418: Factorisation triples

[ ] Problem 419: Look and say sequence

[ ] Problem 420: 2x2 positive integer matrix

[ ] Problem 421: Prime factors of n15+1

[ ] Problem 422: Sequence of points on a hyperbola

[ ] Problem 423: Consecutive die throws

[ ] Problem 424: Kakuro

[ ] Problem 425: Prime connection

[ ] Problem 426: Box-ball system

[ ] Problem 427: n-sequences

[ ] Problem 428: Necklace of Circles

[ ] Problem 429: Sum of squares of unitary divisors

[ ] Problem 430: Range flips

[ ] Problem 431: Square Space Silo

[ ] Problem 432: Totient sum

[ ] Problem 433: Steps in Euclid's algorithm

[ ] Problem 434: Rigid graphs

[ ] Problem 435: Polynomials of Fibonacci numbers

[ ] Problem 436: Unfair wager

[ ] Problem 437: Fibonacci primitive roots

[ ] Problem 438: Integer part of polynomial equation's solutions

[ ] Problem 439: Sum of sum of divisors

[ ] Problem 440: GCD and Tiling

[ ] Problem 441: The inverse summation of coprime couples

[ ] Problem 442: Eleven-free integers

[ ] Problem 443: GCD sequence

[ ] Problem 444: The Roundtable Lottery

[ ] Problem 445: Retractions A

[ ] Problem 446: Retractions B

[ ] Problem 447: Retractions C

[ ] Problem 448: Average least common multiple

[ ] Problem 449: Chocolate covered candy

[ ] Problem 450: Hypocycloid and Lattice points

[ ] Problem 451: Modular inverses

[ ] Problem 452: Long Products

[ ] Problem 453: Lattice Quadrilaterals

[ ] Problem 454: Diophantine reciprocals III

[ ] Problem 455: Powers With Trailing Digits

[ ] Problem 456: Triangles containing the origin II

[ ] Problem 457: A polynomial modulo the square of a prime

[ ] Problem 458: Permutations of Project

[ ] Problem 459: Flipping game

[ ] Problem 460: An ant on the move

[ ] Problem 461: Almost Pi

[ ] Problem 462: Permutation of 3-smooth numbers

[ ] Problem 463: A weird recurrence relation

[ ] Problem 464: Möbius function and intervals

[ ] Problem 465: Polar polygons

[ ] Problem 466: Distinct terms in a multiplication table

[ ] Problem 467: Superinteger

[ ] Problem 468: Smooth divisors of binomial coefficients

[ ] Problem 469: Empty chairs

[ ] Problem 470: Super Ramvok

[ ] Problem 471: Triangle inscribed in ellipse

[ ] Problem 472: Comfortable Distance II

[ ] Problem 473: Phigital number base

[ ] Problem 474: Last digits of divisors

[ ] Problem 475: Music festival

[ ] Problem 476: Circle Packing II

[ ] Problem 477: Number Sequence Game

[ ] Problem 478: Mixtures

[ ] Problem 479: Roots on the Rise

[ ] Problem 480: The Last Question

rafaelgeronimo / freeCodeCamp

Project Euler #41