$$4040 x \left(x x + 1\right)^{2019}$$
2018
/ 2\ / 2\
4040*\1 + x / *\1 + 4039*x /
$$4040 \left(x^{2} + 1\right)^{2018} \left(4039 x^{2} + 1\right)$$
2017
/ 2\ / 2\
16313520*x*\1 + x / *\3 + 4039*x /
$$16313520 x \left(x^{2} + 1\right)^{2017} \left(4039 x^{2} + 3\right)$$