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

typedef long long int ll;
ll MOD = 1000000007;
ll INFL = 1ll << 60;
ll INF = 1 << 30;

// mod. m での a の逆元 a^{-1} を計算する
ll modinv(ll a, ll m) {
  ll b = m, u = 1, v = 0;
  while (b) {
    ll t = a / b;
    a -= t * b;
    swap(a, b);
    u -= t * v;
    swap(u, v);
  }
  u %= m;
  if (u < 0) u += m;
  return u;
}

ll nCr(ll n, ll r) {
  if (r * 2 > n) r = n - r;
  ll res = 1;
  for (int i = 0; i < r; i++) {
    res = res * (n - i) % MOD;
  }
  for (int i = 1; i <= r; i++) {
    res = res * modinv(i, MOD) % MOD;
  }
  return res;
}

int main() {
  int n;
  cin >> n;
  ll a, ans = 0;
  for (int i = 0; i < n; i++) {
    cin >> a;
    ans = (ans + nCr(n - 1, i) * a % MOD) % MOD;
  }
  cout << ans << endl;
}