\[ x^4 y'(x)-x^3 y(x)+y''(x)=0 \] ✓ Mathematica : cpu = 0.0877516 (sec), leaf count = 39
\[\left \{\left \{y(x)\to c_1 x-\frac {c_2 \sqrt [5]{x^5} \Gamma \left (-\frac {1}{5},\frac {x^5}{5}\right )}{5 \sqrt [5]{5}}\right \}\right \}\] ✓ Maple : cpu = 0.085 (sec), leaf count = 56
\[\left \{y \left (x \right ) = \frac {\left (c_{2} x^{2} \WhittakerM \left (\frac {2}{5}, \frac {9}{10}, \frac {x^{5}}{5}\right ) {\mathrm e}^{-\frac {x^{5}}{10}}+c_{1}\right ) x^{8}+9 c_{2} \left (x^{5}+4\right ) \WhittakerM \left (\frac {7}{5}, \frac {9}{10}, \frac {x^{5}}{5}\right ) {\mathrm e}^{-\frac {x^{5}}{10}}}{x^{7}}\right \}\]