Elementary methods in number theory Theorem 1.12 $v_p(n!)=\sum_{r=1}^{[\log_p n]}[\frac{n}{p^r}...

For every positive integer $n$ and prime $p$,
\begin{equation}
v_p(n!)=\sum_{r=1}^{[\log_p n]}[\frac{n}{p^r}]
\end{equation}

This formula is obvious(Why?).

转载于:https://www.cnblogs.com/yeluqing/archive/2012/11/28/3828070.html