打表水过：
#include<iostream> using namespace std; int n; long long a[20] = {0,2,7,5,30,169,441,1872,7632,1740,93313,459901,1358657,2504881,0}; int main() { while(cin>>n && n!=0){ cout<<a[n]<<endl; } return 0; }
原文：http://www.cnblogs.com/forever97/p/3520924.html