\[ \boxed { {x}^{2}{\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left ( x \right ) + \left ( 1+x \right ) {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) -y \left ( x \right ) =0} \]
Mathematica: cpu = 0.799102 (sec), leaf count = 54 \[ \left \{\left \{y(x)\to \text {DifferentialRoot}\left (\{\unicode {f818},\unicode {f817}\}\unicode {f4a1}\left \{\unicode {f818}^{(3)}(\unicode {f817}) \unicode {f817}^2-\unicode {f818}(\unicode {f817})+(\unicode {f817}+1) \unicode {f818}''(\unicode {f817})=0,\unicode {f818}(1)=c_1,\unicode {f818}'(1)=c_2,\unicode {f818}''(1)=c_3\right \}\right )(x)\right \}\right \} \]
Maple: cpu = 0.218 (sec), leaf count = 36 \[ \left \{ y \left ( x \right ) ={\it DESol} \left ( \left \{ -{\it \_Y} \left ( x \right ) + \left ( 1+x \right ) {\frac {{\rm d}^{2}}{{\rm d}{x} ^{2}}}{\it \_Y} \left ( x \right ) +{x}^{2}{\frac {{\rm d}^{3}}{{\rm d}{ x}^{3}}}{\it \_Y} \left ( x \right ) \right \} , \left \{ {\it \_Y} \left ( x \right ) \right \} \right ) \right \} \]