\[ \frac {1}{4} \left (a^2-1\right ) y(x)+a y'(x)+b y(x)^n+y''(x)=0 \] ✗ Mathematica : cpu = 16.7411 (sec), leaf count = 0 , could not solve
DSolve[((-1 + a^2)*y[x])/4 + b*y[x]^n + a*Derivative[1][y][x] + Derivative[2][y][x] == 0, y[x], x]
✓ Maple : cpu = 1.225 (sec), leaf count = 63
\[\left \{y \left (x \right ) = \mathit {ODESolStruc} \left (\textit {\_a} , \left [\left \{\frac {\textit {\_a} \,a^{2}}{4}+a \textit {\_}b\left (\textit {\_a} \right )+b \,\textit {\_a}^{n}+\textit {\_}b\left (\textit {\_a} \right ) \left (\frac {d}{d \textit {\_a}}\mathrm {\_}\mathrm {b}\left (\textit {\_a} \right )\right )-\frac {\textit {\_a}}{4}=0\right \}, \left \{\textit {\_a} =y \left (x \right ), \textit {\_}b\left (\textit {\_a} \right )=\frac {d}{d x}y \left (x \right )\right \}, \left \{x =c_{1}+\int \frac {1}{\textit {\_}b\left (\textit {\_a} \right )}d \textit {\_a} , y \left (x \right )=\textit {\_a} \right \}\right ]\right )\right \}\]