DSolve[Derivative[1][y][x] == (1 + 2*x^2 - x^3 - 4*x^3*y[x] + 3*x^4*y[x] + x^4*y[x]^2 - 3*x^5*y[x]^2 + x^6*y[x]^3)/x^4,y[x],x]