\[ \boxed { {x}^{4}{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) -x \left ( {x}^{2}+2\,y \left ( x \right ) \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) +4\, \left ( y \left ( x \right ) \right ) ^{2}=0} \]
Mathematica: cpu = 0.069509 (sec), leaf count = 262 \[ \left \{\left \{y(x)\to -\frac {x^3 \left (i \left (-\frac {\sqrt {-c_1-1}}{\sqrt {c_1}}+\frac {i}{\sqrt {c_1}}\right ) \sqrt {c_1} c_2 x^{-1+i \left (-\frac {\sqrt {-c_1-1}}{\sqrt {c_1}}+\frac {i}{\sqrt {c_1}}\right ) \sqrt {c_1}}+i \left (\frac {\sqrt {-c_1-1}}{\sqrt {c_1}}+\frac {i}{\sqrt {c_1}}\right ) \sqrt {c_1} x^{-1+i \left (\frac {\sqrt {-c_1-1}}{\sqrt {c_1}}+\frac {i}{\sqrt {c_1}}\right ) \sqrt {c_1}}\right )}{c_2 x^{i \left (-\frac {\sqrt {-c_1-1}}{\sqrt {c_1}}+\frac {i}{\sqrt {c_1}}\right ) \sqrt {c_1}}+x^{i \left (\frac {\sqrt {-c_1-1}}{\sqrt {c_1}}+\frac {i}{\sqrt {c_1}}\right ) \sqrt {c_1}}}\right \}\right \} \]
Maple: cpu = 1.544 (sec), leaf count = 23 \[ \left \{ y \left ( x \right ) =\tanh \left ( -\ln \left ( x \right ) {\it \_C1}+{\it \_C2}\,{\it \_C1} \right ) {x}^{2}{\it \_C1}+{x}^{2} \right \} \]