P110.11.0.99.6            Suppose that a1 ,a2 ,...,an are integers such that a1 + 2ia2 + 3ia3 + ···+ nian = 0 for i = 1,2,...,k − 1, where k ≥ 2 is a given integer. Prove that a1 +2ka2 +3ka3 +···+nkan is divisible by k!.