UVa 12149 - Feynman

#include<bits/stdc++.h>
#define ll long long

using namespace std;

ll fynman(ll n)
{
 if(n==0) return 0;
 else return n*n + fynman(n-1);
}

int main()
{
 ll n;
 
 while(cin>>n && n)
 {
  ll f=fynman(n);
  cout<<f<<endl;
 }
 
 return 0;
}