2020 (x*x + 1)
(x*x + 1)^2020
2019 4040*x*(x*x + 1)
2018 / 2\ / 2\ 4040*\1 + x / *\1 + 4039*x /
2017 / 2\ / 2\ 16313520*x*\1 + x / *\3 + 4039*x /