\[ \boxed { x{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) -2\,{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) +ay \left ( x \right ) =0} \]
Mathematica: cpu = 0.025503 (sec), leaf count = 64 \[ \left \{\left \{y(x)\to 6 a^{3/2} c_1 x^{3/2} J_3\left (2 \sqrt {a} \sqrt {x}\right )-2 i a^{3/2} c_2 x^{3/2} Y_3\left (2 \sqrt {a} \sqrt {x}\right )\right \}\right \} \]
Maple: cpu = 0.016 (sec), leaf count = 35 \[ \left \{ y \left ( x \right ) ={\it \_C1}\,{x}^{{\frac {3}{2}}}{{\sl J} _{3}\left (2\,\sqrt {a}\sqrt {x}\right )}+{\it \_C2}\,{x}^{{\frac {3}{2} }}{{\sl Y}_{3}\left (2\,\sqrt {a}\sqrt {x}\right )} \right \} \]