[求助]一道prep数学题

CCAML

For every positive even integer n, the function h(n) is defined to be the production of all the even integers from 2 to n, inclusive. If p is the smallest prime factor of h(100)+1, then P is:

1. between 2 and 10

2. between 10 and 20

3. between 20 and 30

4. bewteen 30 and 40

5. greater than 40.

答案是最后一个。 一点思路也没有。 请NN指教。

谢谢

[此贴子已经被作者于2009/9/14 9:36:42编辑过]

jadeyang

顶一下，求助求助

owenwei

h(100)=2*4*6*...*100

他一定被2，3，5，7，11，13，。。。47等所有小于等于47的质数整除

那么他+1 就一定不能被这些数整除

答案是e

jadeyang

太牛了，我看了答案想了半天才明白