\[ y''(x)-y(x)^2=0 \] ✓ Mathematica : cpu = 0.0323262 (sec), leaf count = 26
DSolve[-y[x]^2 + Derivative[2][y][x] == 0,y[x],x]
\[\left \{\left \{y(x)\to \sqrt [3]{6} \wp \left (\frac {x+c_1}{\sqrt [3]{6}};0,c_2\right )\right \}\right \}\] ✓ Maple : cpu = 0.753 (sec), leaf count = 12
dsolve(diff(diff(y(x),x),x)-y(x)^2=0,y(x))
\[y \left (x \right ) = 6 \WeierstrassP \left (x +c_{1}, 0, c_{2}\right )\]