\[
\boxed{
{x}^{2}{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) + \left( -{x}^{4}+ \left( 2\,n+2\,a+1 \right) {x}^{2}+ \left( -1 \right) ^{n}a-{a}^{2} \right) y \left( x \right) =0}
\]