\[ \left (-a^2 x^2-a\right ) y(x)+y''(x)=0 \] ✓ Mathematica : cpu = 0.0123819 (sec), leaf count = 43
DSolve[(-a - a^2*x^2)*y[x] + Derivative[2][y][x] == 0,y[x],x]
\[\left \{\left \{y(x)\to c_1 D_{-1}\left (\sqrt {2} \sqrt {a} x\right )+c_2 D_0\left (i \sqrt {2} \sqrt {a} x\right )\right \}\right \}\] ✓ Maple : cpu = 0.04 (sec), leaf count = 22
dsolve(diff(diff(y(x),x),x)-(a^2*x^2+a)*y(x)=0,y(x))
\[y \left (x \right ) = {\mathrm e}^{\frac {a \,x^{2}}{2}} \left (\erf \left (\sqrt {a}\, x \right ) c_{2}+c_{1}\right )\]