※ 引述《jerry900287 ()》之铭言:
: 如图 http://i.imgur.com/vTDlhAG.png
: 想请教各位大大
: 看了解答之后
: 题目的(mod m)是用来干嘛的QQ
: 感觉好像没有什么用处阿
n为整数
a_(n-1) = (n-1)! (mod m)
=> na_(n-1) = n[(n-1)!] (mod m)
=> na_(n-1) = n! (mod m)
又因为a_n = n! (mod m)
=> a_n = na_(n-1) (mod m) for n >= 2
因为a_1 = 1 (mod m)
可令a_0 = 1
使a_n = na_(n-1) (mod m) for n >= 1