(w_n^0=1) (w_n^1=(模数的原根)^{(mod-1)/n}) (w_n^m=w_n^{m-1} cdot w_n^1)
https://www.cnblogs.com/owenyu/p/6724661.html
https://www.cnblogs.com/Parsnip/p/11530658.html