\[ y''(x)-\left (a+x^2\right ) y(x)=0 \] ✓ Mathematica : cpu = 0.007156 (sec), leaf count = 47
\[\left \{\left \{y(x)\to c_1 D_{\frac {1}{2} (-a-1)}\left (\sqrt {2} x\right )+c_2 D_{\frac {a-1}{2}}\left (i \sqrt {2} x\right )\right \}\right \}\] ✓ Maple : cpu = 0.49 (sec), leaf count = 29
\[ \left \{ y \left ( x \right ) ={ \left ( {\it \_C2}\,{{\sl W}_{-{\frac {a}{4}},\,{\frac {1}{4}}}\left ({x}^{2}\right )}+{\it \_C1}\,{{\sl M}_{-{\frac {a}{4}},\,{\frac {1}{4}}}\left ({x}^{2}\right )} \right ) {\frac {1}{\sqrt {x}}}} \right \} \]