\[ \boxed { {x}^{3}{\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left ( x \right ) + \left ( -{\nu }^{2}+1 \right ) x{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) + \left ( a{x}^{3}+{\nu }^{2}-1 \right ) y \left ( x \right ) =0} \]
Mathematica: cpu = 0.777099 (sec), leaf count = 143 \[ \left \{\left \{y(x)\to c_2 3^{\nu -1} a^{\frac {1-\nu }{3}} x^{1-\nu } \, _0F_2\left (;1-\frac {2 \nu }{3},1-\frac {\nu }{3};-\frac {a x^3}{27}\right )+c_3 3^{-\nu -1} a^{\frac {\nu +1}{3}} x^{\nu +1} \, _0F_2\left (;\frac {\nu }{3}+1,\frac {2 \nu }{3}+1;-\frac {a x^3}{27}\right )+\frac {1}{3} \sqrt [3]{a} c_1 x \, _0F_2\left (;1-\frac {\nu }{3},\frac {\nu }{3}+1;-\frac {a x^3}{27}\right )\right \}\right \} \]
Maple: cpu = 0.125 (sec), leaf count = 81 \[ \left \{ y \left ( x \right ) ={\it \_C1}\,x {\mbox {$_0$F$_2$}(\ ;\,{\frac {\nu }{3}}+1,-{\frac {\nu }{3}}+1;\,-{\frac {a{x}^{3}}{27}})} +{\it \_C2}\,{x}^{-\nu +1} {\mbox {$_0$F$_2$}(\ ;\,1-{\frac {2\,\nu }{3}},-{\frac {\nu }{3}}+1;\,-{\frac {a{x}^{3}}{27}})} +{\it \_C3}\,{x}^{\nu +1} {\mbox {$_0$F$_2$}(\ ;\,{\frac {2\,\nu }{3}}+1,{\frac {\nu }{3}}+1;\,-{\frac {a{x}^{3}}{27}})} \right \} \]