\[ y'(x)=\frac {x^{5/3}}{x^{4/3}+y(x)} \] ✓ Mathematica : cpu = 50.4989 (sec), leaf count = 9837
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✓ Maple : cpu = 1.454 (sec), leaf count = 46
\[ \left \{ y \left ( x \right ) ={\frac {1}{2} \left ( {\it RootOf} \left ( {{\it \_Z}}^{192}+12\,{x}^{4/3}{{\it \_Z}}^{176}+48\,{x}^{8/3}{{\it \_Z}}^{160}+64\,{x}^{4}{{\it \_Z}}^{144}-{\it \_C1} \right ) \right ) ^{16}}+{\frac {1}{2}{x}^{{\frac {4}{3}}}} \right \} \]