\[ a x^m+y'(x)+y(x)^2=0 \] ✓ Mathematica : cpu = 0.0297844 (sec), leaf count = 254
\[\left \{\left \{y(x)\to -\frac {i \sqrt {-a} x^{\frac {m+2}{2}} \left (c_1 J_{\frac {m+1}{m+2}}\left (\frac {2 i \sqrt {-a} x^{\frac {m}{2}+1}}{m+2}\right )-c_1 J_{-\frac {m+3}{m+2}}\left (\frac {2 i \sqrt {-a} x^{\frac {m+2}{2}}}{m+2}\right )-2 J_{\frac {1}{m+2}-1}\left (\frac {2 i \sqrt {-a} x^{\frac {m+2}{2}}}{m+2}\right )\right )-c_1 J_{-\frac {1}{m+2}}\left (\frac {2 i \sqrt {-a} x^{\frac {m+2}{2}}}{m+2}\right )}{2 x \left (c_1 J_{-\frac {1}{m+2}}\left (\frac {2 i \sqrt {-a} x^{\frac {m+2}{2}}}{m+2}\right )+J_{\frac {1}{m+2}}\left (\frac {2 i \sqrt {-a} x^{\frac {m+2}{2}}}{m+2}\right )\right )}\right \}\right \}\]
✓ Maple : cpu = 0.108 (sec), leaf count = 187
\[ \left \{ y \left ( x \right ) ={\frac {1}{x} \left ( -\sqrt {a}{x}^{{\frac {m}{2}}+1}{{\sl J}_{{\frac {3+m}{m+2}}}\left (2\,{\frac {\sqrt {a}{x}^{m/2+1}}{m+2}}\right )}{\it \_C1}-{{\sl Y}_{{\frac {3+m}{m+2}}}\left (2\,{\frac {\sqrt {a}{x}^{m/2+1}}{m+2}}\right )}\sqrt {a}{x}^{{\frac {m}{2}}+1}+{\it \_C1}\,{{\sl J}_{ \left ( m+2 \right ) ^{-1}}\left (2\,{\frac {\sqrt {a}{x}^{m/2+1}}{m+2}}\right )}+{{\sl Y}_{ \left ( m+2 \right ) ^{-1}}\left (2\,{\frac {\sqrt {a}{x}^{m/2+1}}{m+2}}\right )} \right ) \left ( {\it \_C1}\,{{\sl J}_{ \left ( m+2 \right ) ^{-1}}\left (2\,{\frac {\sqrt {a}{x}^{m/2+1}}{m+2}}\right )}+{{\sl Y}_{ \left ( m+2 \right ) ^{-1}}\left (2\,{\frac {\sqrt {a}{x}^{m/2+1}}{m+2}}\right )} \right ) ^{-1}} \right \} \]