\[ \left (1-3 y(x)^2\right ) y'(x)^2+y(x) \left (y(x)^2+1\right ) y''(x)=0 \] ✓ Mathematica : cpu = 0.467093 (sec), leaf count = 84
\[\left \{\left \{y(x)\to -\frac {\sqrt {-2 c_1 x-1-2 c_2 c_1}}{\sqrt {2} \sqrt {c_1 x+c_2 c_1}}\right \},\left \{y(x)\to \frac {\sqrt {-2 c_1 x-1-2 c_2 c_1}}{\sqrt {2} \sqrt {c_1 x+c_2 c_1}}\right \}\right \}\] ✓ Maple : cpu = 0.213 (sec), leaf count = 60
\[ \left \{ y \left ( x \right ) ={\frac {1}{2\,{\it \_C1}\,x+2\,{\it \_C2}}\sqrt {-4\, \left ( {\it \_C1}\,x+{\it \_C2}+1/2 \right ) \left ( {\it \_C1}\,x+{\it \_C2} \right ) }},y \left ( x \right ) =-{\frac {1}{2\,{\it \_C1}\,x+2\,{\it \_C2}}\sqrt {-4\, \left ( {\it \_C1}\,x+{\it \_C2}+1/2 \right ) \left ( {\it \_C1}\,x+{\it \_C2} \right ) }} \right \} \]