Wrong TeX make all text disappear

[oovm]

some text

wrong tex:

$$\begin{aligned}
{\left( {n - k} \right)^2} + \left( {n - k} \right) + 41 &= 0,0 < k < 40 \\
{n^2} + \left( {1 - 2k} \right)n + \left( {{k^2} - k + 41} \right) &= 0\\
\left| {{k^2} - k + 41} \right| &< 1000\\
k \leqslant \left\lfloor {\frac{{1 + \sqrt {3837} }}{2}} \right\rfloor &= 31
\end{aligned}$$

some text

I think at least wrong tex should show as raw text.