\[ y(x) \left (a (\nu -1) x^{2 \nu }+b x^{3 \nu }+\nu ^2-1\right )+x \left (a x^{2 \nu }-\nu ^2+1\right ) y'(x)+x^3 y^{(3)}(x)=0 \] ✓ Mathematica : cpu = 0.0353295 (sec), leaf count = 102
\[\left \{\left \{y(x)\to c_1 x^{1-\nu } e^{\frac {x^{\nu } \text {Root}\left [\text {$\#$1}^3+\text {$\#$1} a+b\& ,1\right ]}{\nu }}+c_2 x^{1-\nu } e^{\frac {x^{\nu } \text {Root}\left [\text {$\#$1}^3+\text {$\#$1} a+b\& ,2\right ]}{\nu }}+c_3 x^{1-\nu } e^{\frac {x^{\nu } \text {Root}\left [\text {$\#$1}^3+\text {$\#$1} a+b\& ,3\right ]}{\nu }}\right \}\right \}\] ✗ Maple : cpu = 0. (sec), leaf count = 0 , result contains DESol
\[ \left \{ y \left ( x \right ) ={\it DESol} \left ( \left \{ {x}^{3}{\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}{\it \_Y} \left ( x \right ) + \left ( {x}^{2\,\nu }ax-{\nu }^{2}x+x \right ) {\frac {\rm d}{{\rm d}x}}{\it \_Y} \left ( x \right ) + \left ( {x}^{2\,\nu }a\nu -a{x}^{2\,\nu }+b{x}^{3\,\nu }+{\nu }^{2}-1 \right ) {\it \_Y} \left ( x \right ) \right \} , \left \{ {\it \_Y} \left ( x \right ) \right \} \right ) \right \} \]