\[ -a x^2 y(x)+3 y''(x)+x y^{(3)}(x)=0 \] ✓ Mathematica : cpu = 0.0238575 (sec), leaf count = 104
\[\left \{\left \{y(x)\to -\frac {2 (-1)^{3/4} \sqrt {2} c_1 \, _0F_2\left (;\frac {1}{2},\frac {3}{4};\frac {a x^4}{64}\right )}{\sqrt [4]{a} x}+c_2 \, _0F_2\left (;\frac {3}{4},\frac {5}{4};\frac {a x^4}{64}\right )+\frac {\sqrt [4]{-1} \sqrt [4]{a} c_3 x \, _0F_2\left (;\frac {5}{4},\frac {3}{2};\frac {a x^4}{64}\right )}{2 \sqrt {2}}\right \}\right \}\] ✓ Maple : cpu = 0.11 (sec), leaf count = 48
\[ \left \{ y \left ( x \right ) ={\it \_C1}\,{\mbox {$_0$F$_2$}(\ ;\,{\frac {3}{4}},{\frac {5}{4}};\,{\frac {a{x}^{4}}{64}})}+{\frac {{\it \_C2}}{x}{\mbox {$_0$F$_2$}(\ ;\,{\frac {1}{2}},{\frac {3}{4}};\,{\frac {a{x}^{4}}{64}})}}+{\it \_C3}\,x{\mbox {$_0$F$_2$}(\ ;\,{\frac {5}{4}},{\frac {3}{2}};\,{\frac {a{x}^{4}}{64}})} \right \} \]