C++ :

#include<bits/stdc++.h>
using namespace std;
int main()
{
    long long sum = 0, s = 1;
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        s = s * i;
        sum += s;
    }
    cout << sum;
    return 0;
}

Python :

# coding=utf-8
n = int(input())
m = 1
x = 0
i = 1
while(i <= n):
    m = m * i
    x += m
    i += 1
print(x)