\[\boxed{\mathbf{258}.}\]
\[\left( n^{5} - 5 \right) \vdots 5 - ?;\ \ n \in N.\]
\[Пусть\ \text{n\ }не\ кратно\ 5,\ тогда\]
\[n = 5n_{1} + 1;\ \ n = 5n_{1} + 2;\ \ \]
\[n = 5n_{1} + 3;\ \ n = 5n_{1} + 4.\]
\[Рассмотрим\ все\ случаи.\]
\[\textbf{а)}\ n = 5n_{1} + 1:\]
\[n^{5} - n = n\left( n^{4} - 1 \right);\]
\[\left( 5n_{1} + 1 \right)\left( \left( 5n_{1} + 1 \right)^{4} - 1 \right) =\]
\[\ \]