题解 | #牛牛学数列4#

#include <stdio.h>

int main() {
    int n = 0;
    
    while (~scanf("%d", &n))
    {
        int sum = 0;
        int tmp = 0;
        for (int i = 1; i <= n; i++)
        {
            tmp += i;
            sum += tmp;
        }
        printf("%d\n", sum);
    }

    return 0;
}