\[ \boxed { x{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) +a{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) +bxy \left ( x \right ) =0} \]
Mathematica: cpu = 0.021003 (sec), leaf count = 64 \[ \left \{\left \{y(x)\to c_1 x^{\frac {1-a}{2}} J_{\frac {a-1}{2}}\left (\sqrt {b} x\right )+c_2 x^{\frac {1-a}{2}} Y_{\frac {a-1}{2}}\left (\sqrt {b} x\right )\right \}\right \} \]
Maple: cpu = 0.031 (sec), leaf count = 45 \[ \left \{ y \left ( x \right ) ={\it \_C1}\,{x}^{-{\frac {a}{2}}+{\frac { 1}{2}}}{{\sl J}_{{\frac {a}{2}}-{\frac {1}{2}}}\left (\sqrt {b}x \right )}+{\it \_C2}\,{x}^{-{\frac {a}{2}}+{\frac {1}{2}}}{{\sl Y}_{{ \frac {a}{2}}-{\frac {1}{2}}}\left (\sqrt {b}x\right )} \right \} \]