\[ y''(x)=-\frac {y(x) \left (a^2 \left (x^2+1\right )^2+m^2-n (n+1) \left (x^2+1\right )\right )}{\left (x^2+1\right )^2}-\frac {2 x y'(x)}{x^2+1} \] ✓ Mathematica : cpu = 0.235702 (sec), leaf count = 229
\[\left \{\left \{y(x)\to c_1 \left (x^2+1\right )^{\frac {\sqrt {m^2}}{2}} \text {HeunC}\left [\frac {1}{4} \left (-a^2-\sqrt {m^2} \left (\sqrt {m^2}+1\right )+\frac {1}{4} \left (\sqrt {(2 n+1)^2}-1\right )^2+\frac {1}{2} \left (\sqrt {(2 n+1)^2}-1\right )\right ),-\frac {a^2}{4},\frac {1}{2},\sqrt {m^2}+1,0,-x^2\right ]+c_2 x \left (x^2+1\right )^{\frac {\sqrt {m^2}}{2}} \text {HeunC}\left [\frac {1}{4} \left (-a^2-\left (\sqrt {m^2}+\frac {1}{2} \left (1-\sqrt {(2 n+1)^2}\right )+1\right ) \left (\sqrt {m^2}+\frac {1}{2} \left (\sqrt {(2 n+1)^2}-1\right )+2\right )\right ),-\frac {a^2}{4},\frac {3}{2},\sqrt {m^2}+1,0,-x^2\right ]\right \}\right \}\] ✓ Maple : cpu = 0.23 (sec), leaf count = 88
\[\left \{y \left (x \right ) = \left (c_{2} x \HeunC \left (0, \frac {1}{2}, m , -\frac {a^{2}}{4}, \frac {1}{4} a^{2}+\frac {1}{4} m^{2}-\frac {1}{4} n^{2}-\frac {1}{4} n +\frac {1}{4}, -x^{2}\right )+c_{1} \HeunC \left (0, -\frac {1}{2}, m , -\frac {a^{2}}{4}, \frac {1}{4} a^{2}+\frac {1}{4} m^{2}-\frac {1}{4} n^{2}-\frac {1}{4} n +\frac {1}{4}, -x^{2}\right )\right ) \left (x^{2}+1\right )^{\frac {m}{2}}\right \}\]