\[ \boxed { 4\, \left ( {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) \right ) y \left ( x \right ) -3\, \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}+4\,y \left ( x \right ) =0} \]
Mathematica: cpu = 0.093512 (sec), leaf count = 43 \[ \left \{\left \{y(x)\to \frac {\left (c_1^2 x^2+2 c_2 c_1^2 x+c_2^2 c_1^2-64\right ){}^2}{256 c_1^2}\right \}\right \} \]
Maple: cpu = 1.654 (sec), leaf count = 67 \[ \left \{ -4\,{\frac {\sqrt {{\it \_C1}\, \left ( y \left ( x \right ) \right ) ^{3/2}+4\,y \left ( x \right ) }}{\sqrt {y \left ( x \right ) }{ \it \_C1}}}-x-{\it \_C2}=0,4\,{\frac {\sqrt {{\it \_C1}\, \left ( y \left ( x \right ) \right ) ^{3/2}+4\,y \left ( x \right ) }}{\sqrt {y \left ( x \right ) }{\it \_C1}}}-x-{\it \_C2}=0,y \left ( x \right ) =0 \right \} \]