\[ x^3 y^{(3)}(x)+(x+3) x^2 y''(x)+5 (x-6) x y'(x)+(4 x+30) y(x)=0 \] ✗ Mathematica : cpu = 434.96 (sec), leaf count = 0 , DifferentialRoot result
\[\left \{\left \{y(x)\to \text {DifferentialRoot}\left (\{\unicode {f818},\unicode {f817}\}\unicode {f4a1}\left \{\unicode {f818}^{(3)}(\unicode {f817}) \unicode {f817}^3+(\unicode {f817}+3) \unicode {f818}''(\unicode {f817}) \unicode {f817}^2+5 (\unicode {f817}-6) \unicode {f818}'(\unicode {f817}) \unicode {f817}+(4 \unicode {f817}+30) \unicode {f818}(\unicode {f817})=0,\unicode {f818}(1)=c_1,\unicode {f818}'(1)=c_2,\unicode {f818}''(1)=c_3\right \}\right )(x)\right \}\right \}\]
✓ Maple : cpu = 0.454 (sec), leaf count = 188
\[ \left \{ y \left ( x \right ) ={\frac {{\it \_C3}\,{{\rm e}^{-x}} \left ( {x}^{8}+28\,{x}^{7}+450\,{x}^{6}+5100\,{x}^{5}+42900\,{x}^{4}+267120\,{x}^{3}+1179360\,{x}^{2}+3326400\,x+4536000 \right ) {\it Ei} \left ( 1,-x \right ) +{\it \_C2}\, \left ( {x}^{8}+28\,{x}^{7}+450\,{x}^{6}+5100\,{x}^{5}+42900\,{x}^{4}+267120\,{x}^{3}+1179360\,{x}^{2}+3326400\,x+4536000 \right ) {{\rm e}^{-x}}+60\,{\it \_C3}\, \left ( {x}^{4}-84\,{x}^{3}+2016\,{x}^{2}-20160\,x+75600 \right ) \ln \left ( x \right ) +{\it \_C3}\,{x}^{7}+29\,{\it \_C3}\,{x}^{6}+480\,{\it \_C3}\,{x}^{5}+ \left ( {\it \_C1}+5612\,{\it \_C3} \right ) {x}^{4}+ \left ( -84\,{\it \_C1}+40152\,{\it \_C3} \right ) {x}^{3}+ \left ( 2016\,{\it \_C1}+654192\,{\it \_C3} \right ) {x}^{2}+ \left ( -20160\,{\it \_C1}-2761920\,{\it \_C3} \right ) x+75600\,{\it \_C1}+27367200\,{\it \_C3}}{{x}^{6}}} \right \} \]