\[ y'(x)=\frac {\left (4 a x-y(x)^2\right )^2}{y(x)} \] ✓ Mathematica : cpu = 0.191234 (sec), leaf count = 105
\[\left \{\left \{y(x)\to -\sqrt {4 a x-\sqrt {2} \sqrt {a} \tanh \left (\frac {2 \sqrt {2} a x-\sqrt {2} c_1}{\sqrt {a}}\right )}\right \},\left \{y(x)\to \sqrt {4 a x-\sqrt {2} \sqrt {a} \tanh \left (\frac {2 \sqrt {2} a x-\sqrt {2} c_1}{\sqrt {a}}\right )}\right \}\right \}\] ✓ Maple : cpu = 0.275 (sec), leaf count = 286
\[\left \{y \left (x \right ) = \frac {\sqrt {4}\, \sqrt {\left (c_{1} {\mathrm e}^{2 \left (-2 a x +\sqrt {2}\, \sqrt {a}\right ) x}+{\mathrm e}^{-2 \left (2 a x +\sqrt {2}\, \sqrt {a}\right ) x}\right ) \left (c_{1} \left (a x -\frac {\sqrt {2}\, \sqrt {a}}{4}\right ) {\mathrm e}^{2 \left (-2 a x +\sqrt {2}\, \sqrt {a}\right ) x}+\left (a x +\frac {\sqrt {2}\, \sqrt {a}}{4}\right ) {\mathrm e}^{-2 \left (2 a x +\sqrt {2}\, \sqrt {a}\right ) x}\right )}}{c_{1} {\mathrm e}^{2 \left (-2 a x +\sqrt {2}\, \sqrt {a}\right ) x}+{\mathrm e}^{-2 \left (2 a x +\sqrt {2}\, \sqrt {a}\right ) x}}, y \left (x \right ) = -\frac {\sqrt {4}\, \sqrt {\left (c_{1} {\mathrm e}^{2 \left (-2 a x +\sqrt {2}\, \sqrt {a}\right ) x}+{\mathrm e}^{-2 \left (2 a x +\sqrt {2}\, \sqrt {a}\right ) x}\right ) \left (c_{1} \left (a x -\frac {\sqrt {2}\, \sqrt {a}}{4}\right ) {\mathrm e}^{2 \left (-2 a x +\sqrt {2}\, \sqrt {a}\right ) x}+\left (a x +\frac {\sqrt {2}\, \sqrt {a}}{4}\right ) {\mathrm e}^{-2 \left (2 a x +\sqrt {2}\, \sqrt {a}\right ) x}\right )}}{c_{1} {\mathrm e}^{2 \left (-2 a x +\sqrt {2}\, \sqrt {a}\right ) x}+{\mathrm e}^{-2 \left (2 a x +\sqrt {2}\, \sqrt {a}\right ) x}}\right \}\]