\[ x^4 y'(x)-x^3 y(x)+y''(x)=0 \] ✓ Mathematica : cpu = 0.0564023 (sec), leaf count = 72
\[\left \{\left \{y(x)\to c_1 x-\frac {c_2 e^{-\frac {x^5}{5}} \left (5 \left (x^5\right )^{4/5}-5^{4/5} e^{\frac {x^5}{5}} x^5 \Gamma \left (\frac {4}{5},\frac {x^5}{5}\right )\right )}{5 \left (x^5\right )^{4/5}}\right \}\right \}\]
✓ Maple : cpu = 0.081 (sec), leaf count = 55
\[ \left \{ y \left ( x \right ) ={\it \_C1}\,x+{\frac {{\it \_C2}}{{x}^{7}}{{\rm e}^{-{\frac {{x}^{5}}{10}}}} \left ( {x}^{10}{{\sl M}_{{\frac {2}{5}},\,{\frac {9}{10}}}\left ({\frac {{x}^{5}}{5}}\right )}+9\,{{\sl M}_{7/5,\,{\frac {9}{10}}}\left (1/5\,{x}^{5}\right )}{x}^{5}+36\,{{\sl M}_{7/5,\,{\frac {9}{10}}}\left (1/5\,{x}^{5}\right )} \right ) } \right \} \]