y'(x)=\frac{1}{512} x \left(a^3 x^{12}+24 a^2 x^8 y(x)+8 a^2 x^8+192 a x^4 y(x)^2+128 a x^4 y(x)-256 a x^2+512 y(x)^3+512 y(x)^2+512\right)