\[(n - 2)^{2}\ :n^{2} = \frac{(n - 2)^{2}}{n^{2}} =\]
\[= \left( \frac{n - 2}{n} \right)^{2} =\]
\[= \left( \frac{n}{n} - \frac{2}{n} \right)^{2} = \left( 1 - \frac{2}{n} \right)^{2} \in Z\ при\ \]
\[n = - 2;\ - 1;1;2.\]