题解 | #牛牛学数列4#

//2
#include<stdio.h>
int main() {
    int val = 0, n, a = 0;
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            a += j;
        }
        val += a;
        a = 0;
    }
    printf("%d", val);
    return 0;
}