Let: $S_m = \sum_{k=0}^n{((-1)^{n-k}}C_n^kk^m)$.
I need to calculate $S_m$ for all $m=0, 1, \ldots, n-1$.
As I undertood, it should be equal to zero for all $n, m$ (according to some computations on my PC). But I have no idea how to solve it more formally.