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