#include <bits/stdc++.h>
using namespace std;

long product_n2k(long n,long k){
    if (n == 0){
        return 1;
    } else if (n == k) {
        return n;
    }else {
        return n * product_n2k(n - 1, k);
    }
}

long bi_coefficient(long n, long k){
    if (k == 0)
        return 1;
    else
        return product_n2k(n, n - k + 1) / product_n2k(k, 1);
}

int main (){
    long long N,x,y;
    long long ans=0;
    cin >> N;
    for(long long i=0;i<N;i++){
        cin >> y;
        x=bi_coefficient(N-1,i);
        ans += y*x;
        ans %= 1000000007;
    }
    cout << ans << endl;
}