摘要
证明自然数方幂和可以用多项式表示，并用两种方法给出其系数的包含Ｂｅｒｎｏｕｌｌｉ数的几种精确表示式。
This paper showed that the power sum of natural numbers could be expressed in terms of the multinomial. By using two methods, several explicit exymssiensinvolving Bernoulli numbers in multinomial coefficients were given.
