\[ x^{10} y^{(5)}(x)-a y(x)=0 \] ✓ Mathematica : cpu = 15.9796 (sec), leaf count = 103
\[\left \{\left \{y(x)\to x^4 \left (c_1 e^{-\frac {\sqrt [5]{a}}{x}}+c_2 e^{\frac {\sqrt [5]{-1} \sqrt [5]{a}}{x}}+c_3 e^{-\frac {(-1)^{2/5} \sqrt [5]{a}}{x}}+c_4 e^{\frac {(-1)^{3/5} \sqrt [5]{a}}{x}}+c_5 e^{-\frac {(-1)^{4/5} \sqrt [5]{a}}{x}}\right )\right \}\right \}\]
✓ Maple : cpu = 0.176 (sec), leaf count = 90
\[ \left \{ y \left ( x \right ) ={\it \_C1}\,{\mbox {$_0$F$_4$}(\ ;\,{\frac {6}{5}},{\frac {7}{5}},{\frac {8}{5}},{\frac {9}{5}};\,-{\frac {a}{3125\,{x}^{5}}})}+{\it \_C2}\,x{\mbox {$_0$F$_4$}(\ ;\,{\frac {4}{5}},{\frac {6}{5}},{\frac {7}{5}},{\frac {8}{5}};\,-{\frac {a}{3125\,{x}^{5}}})}+{\it \_C3}\,{x}^{2}{\mbox {$_0$F$_4$}(\ ;\,{\frac {3}{5}},{\frac {4}{5}},{\frac {6}{5}},{\frac {7}{5}};\,-{\frac {a}{3125\,{x}^{5}}})}+{\it \_C4}\,{x}^{3}{\mbox {$_0$F$_4$}(\ ;\,{\frac {2}{5}},{\frac {3}{5}},{\frac {4}{5}},{\frac {6}{5}};\,-{\frac {a}{3125\,{x}^{5}}})}+{\it \_C5}\,{x}^{4}{\mbox {$_0$F$_4$}(\ ;\,{\frac {1}{5}},{\frac {2}{5}},{\frac {3}{5}},{\frac {4}{5}};\,-{\frac {a}{3125\,{x}^{5}}})} \right \} \]