#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>
#include <string>
typedef long long ll;
#define MOD 1000000007
using namespace std;

int main(){
    int N, a;
    ll s, c;
    cin >> N;
    c = 1;
    cin >> a;
    s = c * a % MOD;
    for(int i = 0; i < N-1; i++)
    {
        cin >> a;
        c = c * (N - 1 - i) / (i + 1);
        s += c * a % MOD;
    }
    cout << s << endl;
    return 0;
}