\[ x y^{(3)}(x)+3 y''(x)+x y(x)=0 \] ✓ Mathematica : cpu = 0.180387 (sec), leaf count = 43
\[\left \{\left \{y(x)\to \frac {c_1 e^{-x}+c_2 e^{\sqrt [3]{-1} x}+c_3 e^{-(-1)^{2/3} x}}{x}\right \}\right \}\]
✓ Maple : cpu = 0.022 (sec), leaf count = 41
\[ \left \{ y \left ( x \right ) ={\frac {1}{x} \left ( {\it \_C1}\,{{\rm e}^{-x}}+{\it \_C2}\,{{\rm e}^{{\frac {x}{2}}}}\sin \left ( {\frac {\sqrt {3}x}{2}} \right ) +{\it \_C3}\,{{\rm e}^{{\frac {x}{2}}}}\cos \left ( {\frac {\sqrt {3}x}{2}} \right ) \right ) } \right \} \]