#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
using ll = long long;

constexpr int P = 1000000007;

int inv(int n) {
    int m = P, y = 0, v = 1;
    while (1) {
        int q = m / n;
        int r = m % n;
        if (r == 0) return v < 0 ? v + P : v;
        y -= v * q;
        swap(y, v);
        m = n;
        n = r;
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;

    int m = n - 1;

    ll s = 0, t = 1;
    for (int i = 0; i <= m; i++) {
        int a;
        cin >> a;

        s += a * t;
        s %= P;

        t = t * (m - i) % P * inv(i + 1) % P;
    }

    cout << s << endl;

    return 0;
}