\[ y^{(3)}(x) y'(x)^3+y^{(4)}(x) y'(x)-y^{(3)}(x) y''(x)=0 \] ✗ Mathematica : cpu = 0.0960456 (sec), leaf count = 0 , could not solve
DSolve[Derivative[1][y][x]^3*Derivative[3][y][x] - Derivative[2][y][x]*Derivative[3][y][x] + Derivative[1][y][x]*Derivative[4][y][x] == 0, y[x], x]
✓ Maple : cpu = 1.661 (sec), leaf count = 164
\[ \left \{ y \left ( x \right ) ={\it ODESolStruc} \left ( \int \!{\frac {{\it \_j} \left ( {\it \_h} \right ) }{{{\rm e}^{\int \!{\it \_j} \left ( {\it \_h} \right ) \,{\rm d}{\it \_h}+{\it \_C2}}}{\it \_h}}}\,{\rm d}{\it \_h}+{\it \_C3},[ \left \{ {\frac {\rm d}{{\rm d}{\it \_h}}}{\it \_j} \left ( {\it \_h} \right ) ={\frac {{\it \_j} \left ( {\it \_h} \right ) \left ( 12\, \left ( {\it \_j} \left ( {\it \_h} \right ) \right ) ^{2}{{\it \_h}}^{2}+3\,{\it \_h}\, \left ( {\it \_j} \left ( {\it \_h} \right ) \right ) ^{2}+10\,{\it \_j} \left ( {\it \_h} \right ) {\it \_h}+{\it \_j} \left ( {\it \_h} \right ) +1 \right ) }{{\it \_h}}} \right \} , \left \{ {\it \_h}={\frac {{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) }{ \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{3}}},{\it \_j} \left ( {\it \_h} \right ) ={\frac { \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{3}{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) }{ \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) {\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left ( x \right ) -3\, \left ( {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) \right ) ^{2}}} \right \} , \left \{ x=\int \!{\frac {{\it \_j} \left ( {\it \_h} \right ) }{{\it \_h}\, \left ( {{\rm e}^{\int \!{\it \_j} \left ( {\it \_h} \right ) \,{\rm d}{\it \_h}+{\it \_C2}}} \right ) ^{2}}}\,{\rm d}{\it \_h}+{\it \_C1},y \left ( x \right ) =\int \!{\frac {{\it \_j} \left ( {\it \_h} \right ) }{{{\rm e}^{\int \!{\it \_j} \left ( {\it \_h} \right ) \,{\rm d}{\it \_h}+{\it \_C2}}}{\it \_h}}}\,{\rm d}{\it \_h}+{\it \_C3} \right \} ] \right ) \right \} \]