B4410 [GESP202509 一级] 金字塔 题解

#include <bits/stdc++.h>
#define int long long
signed main(){
	int n,ans = 0; std::cin >> n;
	for(int i = n;i >= 1;i--) ans += i*i;//枚举 
	std::cout << ans;
	return 0;
}