#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
struct mint {
  long long x;
  mint(long long x = 0) : x((x % mod + mod) % mod) {}
  mint operator-() const { return mint(-x); }
  mint& operator+=(const mint& a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint& a) {
    if ((x += mod - a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint& a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint& a) const { return mint(*this) += a; }
  mint operator-(const mint& a) const { return mint(*this) -= a; }
  mint operator*(const mint& a) const { return mint(*this) *= a; }
  mint pow(long long t) const {
    if (!t) return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1) a *= *this;
    return a;
  }
  mint inv() const { return pow(mod - 2); }
  mint& operator/=(const mint& a) { return *this *= a.inv(); }
  mint operator/(const mint& a) const { return mint(*this) /= a; }
};
istream& operator>>(istream& is, const mint& a) { return is >> a.x; }
ostream& operator<<(ostream& os, const mint& a) { return os << a.x; }
int main() {
  int n;
  cin >> n;
  vector<mint> x(n);
  for (int i = 0; i < (int)(n); ++i) {
    int a;
    cin >> a;
    x[i] = a;
  }
  vector<mint> s(n + 1);
  for (int i = n - 1; i >= 0; i--) {
    s[i] = s[i + 1] + x[i];
  }
  mint ans = 0;
  for (int i = 0; i < (int)(n - 1); ++i) {
    if (i == 0) {
      ans += s[i + 1] - x[i] * (n - i - 1);
    } else {
      ans += (s[i + 1] - x[i] * (n - i - 1)) * 2;
    }
  }
  for (int i = 0; i < (int)(n - 2); ++i) {
    ans *= (i + 1);
  }
  cout << ans << endl;
  return (0);
}
