\[ \boxed { {x}^{2\,n+1}{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) -a \left ( y \left ( x \right ) \right ) ^{3}-b{x}^{3\,n}=0} \]
Mathematica: cpu = 21.064175 (sec), leaf count = 33 \[ \text {DSolve}\left [-a y(x)^3-b n x^3+x^{2 n+1} y'(x)=0,y(x),x\right ] \]
Maple: cpu = 0.031 (sec), leaf count = 32 \[ \left \{ y \left ( x \right ) ={\it RootOf} \left ( -\ln \left ( x \right ) +{\it \_C1}+\int ^{{\it \_Z}}\! \left ( {{\it \_a}}^{3}a-n{ \it \_a}+b \right ) ^{-1}{d{\it \_a}} \right ) {x}^{n} \right \} \]