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

#define INF_LL (int64)1e18
#define INF (int32)1e9
#define REP(i, n) for(int64 i = 0;i < (n);i++)
#define FOR(i, a, b) for(int64 i = (a);i < (b);i++)
#define all(x) x.begin(),x.end()
#define fs first
#define sc second

using int32 = int_fast32_t;
using uint32 = uint_fast32_t;
using int64 = int_fast64_t;
using uint64 = uint_fast64_t;
using PII = pair<int32, int32>;
using PLL = pair<int64, int64>;

const double eps = 1e-10;

template<typename A, typename B>inline void chmin(A &a, B b){if(a > b) a = b;}
template<typename A, typename B>inline void chmax(A &a, B b){if(a < b) a = b;}

template<typename T>
vector<T> make_v(size_t a){return vector<T>(a);}

template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts){
	return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}

template<typename T,typename U,typename... V>
typename enable_if<is_same<T, U>::value!=0>::type
fill_v(U &u,const V... v){u=U(v...);}

template<typename T,typename U,typename... V>
typename enable_if<is_same<T, U>::value==0>::type
fill_v(U &u,const V... v){
	for(auto &e:u) fill_v<T>(e,v...);
}

template<::std::uint_fast64_t mod>
class ModInt{
private:
  using value_type = ::std::uint_fast64_t;
  value_type n;
public:
  ModInt() : n(0) {}
  ModInt(value_type n_) : n(n_ % mod) {}
  ModInt(const ModInt& m) : n(m.n) {}

  template<typename T>
  explicit operator T() const { return static_cast<T>(n); }
  value_type get() const { return n; }

  friend ::std::ostream& operator<<(::std::ostream &os, const ModInt<mod> &a) {
    return os << a.n;
  }

  friend ::std::istream& operator>>(::std::istream &is, ModInt<mod> &a) {
    value_type x;
    is >> x;
    a = ModInt<mod>(x);
    return is;
  }

  bool operator==(const ModInt& m) const { return n == m.n; }
  bool operator!=(const ModInt& m) const { return n != m.n; }
  ModInt& operator*=(const ModInt& m){ n = n * m.n % mod; return *this; }

  ModInt pow(value_type b) const{
    ModInt ans = 1, m = ModInt(*this);
    while(b){
      if(b & 1) ans *= m;
      m *= m;
      b >>= 1;
    }
    return ans;
  }

  ModInt inv() const { return (*this).pow(mod-2); }
  ModInt& operator+=(const ModInt& m){ n += m.n; n = (n < mod ? n : n - mod); return *this; }
  ModInt& operator-=(const ModInt& m){ n += mod - m.n; n = (n < mod ? n : n - mod); return *this; }
  ModInt& operator/=(const ModInt& m){ *this *= m.inv(); return *this; }
  ModInt operator+(const ModInt& m) const { return ModInt(*this) += m; }
  ModInt operator-(const ModInt& m) const { return ModInt(*this) -= m; }
  ModInt operator*(const ModInt& m) const { return ModInt(*this) *= m; }
  ModInt operator/(const ModInt& m) const { return ModInt(*this) /= m; }
  ModInt& operator++(){ n += 1; return *this; }
  ModInt& operator--(){ n -= 1; return *this; }
  ModInt operator++(int){
    ModInt old(n);
    n += 1;
    return old;
  }
  ModInt operator--(int){
    ModInt old(n);
    n -= 1;
    return old;
  }
  ModInt operator-() const { return ModInt(mod-n); }
};

template<::std::size_t size, ::std::uint_fast64_t mod=1000000007>
class Factorial{
private:
  using value_type = ModInt<mod>;
  ::std::vector<value_type> fact, inv;
public:
  Factorial() : fact(size+1, 1), inv(size+1, 1){
    for(::std::size_t i = 1; i <= size; ++i){
      fact[i] = fact[i-1] * value_type(i);
      inv[i] = fact[i].inv();
    }
  }

  value_type comb(::std::int64_t a, ::std::int64_t b){
    assert(a >= b);
    assert(b >= 0);
    return fact[a]*inv[b]*inv[a-b];
  }

  value_type& operator[](::std::size_t k){ return fact[k]; }
};

constexpr int64 mod = 1e9+7;
using Mint = ModInt<mod>;
Factorial<212345> f;

int main(void){
	cin.tie(0);
	ios::sync_with_stdio(false);

	int64 N;
	cin >> N;
	vector<int64> x(N);
	REP(i, N) cin >> x[i];
	Mint res = 0;
//	vector<Mint> sumr(N, 0), suml(N, 0);
//	REP(i, N-1) {
//	  FOR(j, i+1, N) {
////	    cout << f[N-(j-i+1)-(j != N-1)] << " " << f[j-i-1] << " " << f.comb(N-1, j-i+(j != N-1)) << ": " << i << " " << j << endl;
//	    res += f[N-(j-i+1)-(j!=N-1)]*f[j-i-1]*f.comb(N-1, j-i+(j != N-1))*(x[j]-x[i]);
//	    suml[i] += f[N-(j-i+1)-(j!=N-1)]*f[j-i-1]*f.comb(N-1, j-i+(j != N-1));
//	    sumr[j] += f[N-(j-i+1)-(j!=N-1)]*f[j-i-1]*f.comb(N-1, j-i+(j != N-1));
//	  }
//	}
//	REP(i, N) cout << suml[i] << " ";
//	cout << endl;
//	REP(i, N) cout << sumr[i] << " ";
//	cout << endl;
  vector<Mint> r(N);
  r[0] = 0;
  REP(i, N-1) {
    if (i != 0) {
      r[i] = Mint(i) * r[i-1] + f[i-1];
//      cout << r[i].get() << " ";
      res -= Mint(x[i]) * f[N-1];
//      res += Mint(x[i]) * f[i] * f[N - i - 2] * f.comb(N - 1, i + 1);
      res += Mint(x[i]) * (f[i]*i) / f[i+1] * f[N-1];
//      cout << f[N-3] * f.comb(N-1, 2) << " " << (f[i]*i) / f[i+1] * f[N-1]<< endl;
    }else {
      res -= Mint(x[i]) * f[N - 1];
//      cout << f[N-1] << endl;
    }
  }
//  cout << endl;
  r[N-1] = Mint(N-1) * r[N-2] + f[N-2];
//  cout << r[N-1] << endl;
  res += Mint(x[N-1]) * r[N-1];
	cout << res << endl;
}


Measured memory_bytes: 5120