\[ \boxed { y \left ( x \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) +ay \left ( x \right ) +1/4\, \left ( {a}^{2}-1 \right ) x+b{x}^{n}=0} \]
Mathematica: cpu = 24.751143 (sec), leaf count = 33 \[ \text {DSolve}\left [\frac {1}{4} \left (a^2-1\right ) x+a y(x)+b x^n+y(x) y'(x)=0,y(x),x\right ] \]
Maple: cpu = 0.967 (sec), leaf count = 0 \[ \text {could not solve} \]