SPOJ 3410 - SAMER08F - Feynman

Problem Statement

Explanation:  How many squares a (4x4) square holds? the answer is-

16 (1x1) squares + 4 (2x2) squares, 9 (3x3) squares, 1 (4x4) squares

Meaning, the answer is n²+ (n-1)²+(n-2)²+.......+1²
which is also equivalent to 
 

Solution:

#include<stdio.h>
int main()
{
    int n,x;
    while(scanf("%d",&n)&&n!=0)
    {
        x=(n*(n+1)*((2*n)+1))/6;
        printf("%d\n",x);
    }
    return 0;
}