#include <cassert>
#include <cmath>
#include <iostream>
#include <vector>
using namespace std;
using i64 = int64_t;

constexpr static int mod = static_cast<int>(pow(10, 9)) + 7;

i64 mod_inv(i64 a, i64 m) {
  i64 b = m, s = 1, t = 0, old_a = a;
  while(b) {
    i64 q = a / b;
    swap(a %= b, b);
    swap(s -= t * q, t);
  }
  if(a != 1) { assert(0); }
  return s < 0 ? s + m : s;
}

class Comb {
 private:
  int N;
 public:
  explicit Comb(int N);
  vector<i64> fac; // fac[x] := x! % mod
  i64 P(int n, int k);
  i64 C(int n, int k);
  i64 H(int n, int k);
};

Comb::Comb(int N_) : N(N_) {
  fac.resize(N+1);
  fac[0] = 1;
  for(int i=0; i<N; ++i) {
    fac[i+1] = fac[i] * (i+1);
    fac[i+1] %= mod;
  }
}

i64 Comb::P(int n, int k) {
  if(n < k) { return 0; }
  return fac[n] * mod_inv(fac[n-k], mod) % mod;
}

i64 Comb::C(int n, int k) {
  if(n < k) { return 0; }
  return fac[n] * mod_inv(fac[n-k], mod) % mod * mod_inv(fac[k], mod) % mod;
}

i64 Comb::H(int n, int k) {
  if(n == 0 && k == 0) { return 1; }
  return C(n+k-1, k);
}

i64 f(int n, const vector<i64> &a) {
  Comb comb(n-1);
  i64 res = 0;
  for(int i=0; i<n; ++i) {
    res += comb.C(n-1, i) * a[i] % mod;
    res %= mod;
  }
  return res;
}

int main(void) {
  int N; scanf("%d", &N);
  vector<i64> a(N);
  for(int i=0; i<N; ++i) { scanf("%ld", &a[i]); }
  i64 res = f(N, a);
  printf("%ld\n", res);
  return 0;
}