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

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;


#define REP(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
#define all(x) (x).begin(),(x).end()
#define m0(x) memset(x,0,sizeof(x))

int dx4[4] = {1,0,-1,0}, dy4[4] = {0,1,0,-1};


template <int M, bool IsPrime = false> class Modulo {
  int n;
  static typename std::enable_if<IsPrime, ll>::type inv(ll a, ll p) {
    return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
  }

public:
  Modulo() : n(0) { ; }
  Modulo(int m) : n(m) {
    if (n >= M)
      n %= M;
    else if (n < 0)
      n = (n % M + M) % M;
  }
  Modulo(ll m) {
    if (m >= M)
      m %= M;
    else if (m < 0)
      m = (m % M + M) % M;
    n = m;
  }
  explicit operator int() const { return n; }
  explicit operator ll() const { return n; }
  bool operator==(const Modulo &a) const { return n == a.n; }
  Modulo &operator+=(const Modulo &a) {
    n += a.n;
    if (n >= M) n -= M;
    return *this;
  }
  Modulo &operator-=(const Modulo &a) {
    n -= a.n;
    if (n < 0) n += M;
    return *this;
  }
  Modulo &operator*=(const Modulo &a) {
    n = (ll(n) * a.n) % M;
    return *this;
  }
  Modulo operator+(const Modulo &a) const {
    Modulo res = *this;
    return res += a;
  }
  Modulo operator-(const Modulo &a) const {
    Modulo res = *this;
    return res -= a;
  }
  Modulo operator-() const { return Modulo(0) - *this; }
  Modulo operator*(const Modulo &a) const {
    Modulo res = *this;
    return res *= a;
  }

  Modulo operator^(ll m) const {
    if (m == 0) return Modulo(1);
    const Modulo a = *this;
    Modulo res = (a * a) ^ (m / 2);
    return m % 2 ? res * a : res;
  }
  typename std::enable_if<IsPrime, Modulo>::type
  operator/(const Modulo &a) const {
    return *this * inv(ll(a), M);
  }
  typename std::enable_if<IsPrime, Modulo>::type operator/=(const Modulo &a) {
    return *this *= inv(ll(a), M);
  }

  friend bool is_zero(const Modulo &x) { return int(x) == 0; }
  friend int abs(const Modulo &x) { return int(x); }

  static Modulo fact(int n, bool sw = true) {
    static std::vector<Modulo> v1 = { 1 }, v2 = { 1 };
    if (n >= (int)v1.size()) {
      const int from = v1.size(), to = n + 1024;
      v1.reserve(to);
      v2.reserve(to);
      for (int i = from; i < to; ++i) {
        v1.push_back(v1.back() * Modulo<M, true>(i));
        v2.push_back(v2.back() / Modulo<M, true>(i));
      }
    }
    return sw ? v1[n] : v2[n];
  }
  static Modulo comb(int a, int b) {
    if (b < 0 || b > a) return 0;
    return Modulo::fact(a, true) * Modulo::fact(b, false) *
           Modulo::fact(a - b, false);
  }
};

using Mod = Modulo<1000000007, true>;

int main()
{
    ll n;
    cin>>n;
    Mod ans=0;
    vector<Mod> x(n);
    for (int i = 0; i < n; i++)
    {
        int j;
        cin>>j;
        x[i]=j;
    }
    
    for (int i = n - 1; i > 0; i--)
    {
        x[i]-=x[i-1];
    }
    for (int i = 0; i < n-1; i++)
    {
        x[i]=x[i+1];
    }
    
    x[n-1]=0;
    
    vector<Mod> kaijo(n+10); //kaijo[i]=i!
    kaijo[0]=1;
    for (ll i = 1; i < n+10; i++)
    {
        kaijo[i]=kaijo[i-1]*i;
    }
    vector<Mod> kaisuu(n);  //tooru kaisuu
    kaisuu[0]=kaijo[n-1];
    for (ll i = 1; i < n; i++)
    {
        kaisuu[i]=kaisuu[i-1]+(kaisuu[0]/(i+1));
    }
    for (ll i = 0; i < n-1; i++)
    {
        ans+=kaisuu[i]*x[i];
    }
    cout<<int(ans)<<endl;

    
    //cout<<"i"<<"\t"<<"x"<<"\t"<<"kaisuu"<<"\t"<<"kaijo"<<endl;

    //for (ll i = 0; i < n; i++)
    //{
    //    cout<<i<<"\t"<<int(x[i])<<"\t"<<int(kaisuu[i])<<"\t"<<int(kaijo[i])<<endl;
    //}
    
    
    return 0;
}

Measured memory_bytes: 1408