#line 1 "main.cpp"
#include <bits/stdc++.h>
#line 2 "/home/ubuntu/Library/utils/macros.hpp"
#define REP(i, n) for (int i = 0; (i) < (int)(n); ++ (i))
#define REP3(i, m, n) for (int i = (m); (i) < (int)(n); ++ (i))
#define REP_R(i, n) for (int i = (int)(n) - 1; (i) >= 0; -- (i))
#define REP3R(i, m, n) for (int i = (int)(n) - 1; (i) >= (int)(m); -- (i))
#define ALL(x) std::begin(x), std::end(x)
#line 2 "/home/ubuntu/Library/modulus/mint.hpp"
#include <algorithm>
#include <cassert>
#include <iostream>
#line 2 "/home/ubuntu/Library/modulus/modpow.hpp"
#include <cassert>

inline constexpr int32_t modpow(uint_fast64_t x, uint64_t k, int32_t MOD) {
    assert (0 <= x and x < MOD);
    uint_fast64_t y = 1;
    for (; k; k >>= 1) {
        if (k & 1) (y *= x) %= MOD;
        (x *= x) %= MOD;
    }
    assert (0 <= y and y < MOD);
    return y;
}
#line 2 "/home/ubuntu/Library/modulus/modinv.hpp"
#include <algorithm>
#include <cassert>

inline int32_t modinv_nocheck(int32_t value, int32_t MOD) {
    assert (0 <= value and value < MOD);
    if (value == 0) return -1;
    int64_t a = value, b = MOD;
    int64_t x = 0, y = 1;
    for (int64_t u = 1, v = 0; a; ) {
        int64_t q = b / a;
        x -= q * u; std::swap(x, u);
        y -= q * v; std::swap(y, v);
        b -= q * a; std::swap(b, a);
    }
    if (not (value * x + MOD * y == b and b == 1)) return -1;
    if (x < 0) x += MOD;
    assert (0 <= x and x < MOD);
    return x;
}

inline int32_t modinv(int32_t x, int32_t MOD) {
    int32_t y = modinv_nocheck(x, MOD);
    assert (y != -1);
    return y;
}
#line 7 "/home/ubuntu/Library/modulus/mint.hpp"


template <int32_t MOD>
struct mint {
    int32_t value;
    mint() : value() {}
    mint(int64_t value_) : value(value_ < 0 ? value_ % MOD + MOD : value_ >= MOD ? value_ % MOD : value_) {}
    mint(int32_t value_, std::nullptr_t) : value(value_) {}
    explicit operator bool() const { return value; }
    inline constexpr mint<MOD> operator + (mint<MOD> other) const { return mint<MOD>(*this) += other; }
    inline constexpr mint<MOD> operator - (mint<MOD> other) const { return mint<MOD>(*this) -= other; }
    inline constexpr mint<MOD> operator * (mint<MOD> other) const { return mint<MOD>(*this) *= other; }
    inline constexpr mint<MOD> & operator += (mint<MOD> other) { this->value += other.value; if (this->value >= MOD) this->value -= MOD; return *this; }
    inline constexpr mint<MOD> & operator -= (mint<MOD> other) { this->value -= other.value; if (this->value <    0) this->value += MOD; return *this; }
    inline constexpr mint<MOD> & operator *= (mint<MOD> other) { this->value = (uint_fast64_t)this->value * other.value % MOD; return *this; }
    inline constexpr mint<MOD> operator - () const { return mint<MOD>(this->value ? MOD - this->value : 0, nullptr); }
    inline constexpr mint<MOD> pow(uint64_t k) const { return mint<MOD>(modpow(value, k, MOD), nullptr); }
    inline mint<MOD> inv() const { return mint<MOD>(modinv(value, MOD), nullptr); }
    inline constexpr mint<MOD> operator /  (mint<MOD> other) const { return *this *  other.inv(); }
    inline constexpr mint<MOD> operator /= (mint<MOD> other)       { return *this *= other.inv(); }
    inline constexpr bool operator == (mint<MOD> other) const { return value == other.value; }
    inline constexpr bool operator != (mint<MOD> other) const { return value != other.value; }
};
template <int32_t MOD> mint<MOD> operator * (int64_t value, mint<MOD> n) { return mint<MOD>(value) * n; }
template <int32_t MOD> std::istream & operator >> (std::istream & in, mint<MOD> & n) { int64_t value; in >> value; n = value; return in; }
template <int32_t MOD> std::ostream & operator << (std::ostream & out, mint<MOD> n) { return out << n.value; }
#line 2 "/home/ubuntu/Library/modulus/factorial.hpp"
#include <vector>
#line 4 "/home/ubuntu/Library/modulus/factorial.hpp"

template <int32_t MOD>
mint<MOD> fact(int n) {
    static std::vector<mint<MOD> > memo(1, 1);
    while (n >= memo.size()) {
        memo.push_back(memo.back() * mint<MOD>(memo.size()));
    }
    return memo[n];
}
template <int32_t MOD>
mint<MOD> inv_fact(int n) {
    static std::vector<mint<MOD> > memo;
    if (memo.size() <= n) {
        int l = memo.size();
        int r = n * 1.3 + 100;
        memo.resize(r);
        memo[r - 1] = fact<MOD>(r - 1).inv();
        for (int i = r - 2; i >= l; -- i) {
            memo[i] = memo[i + 1] * (i + 1);
        }
    }
    return memo[n];
}
#line 2 "/home/ubuntu/Library/modulus/choose.hpp"
#include <cassert>
#line 6 "/home/ubuntu/Library/modulus/choose.hpp"

/**
 * @note O(n log n) at first time, otherwise O(1)
 */
template <int32_t MOD>
mint<MOD> choose(int n, int r) {
    assert (0 <= r and r <= n);
    return fact<MOD>(n) * inv_fact<MOD>(n - r) * inv_fact<MOD>(r);
}
template <int32_t MOD>
mint<MOD> permute(int n, int r) {
    assert (0 <= r and r <= n);
    return fact<MOD>(n) * inv_fact<MOD>(n - r);
}
template <int32_t MOD>
mint<MOD> multichoose(int n, int r) {
    assert (0 <= n and 0 <= r);
    if (n == 0 and r == 0) return 1;
    return choose<MOD>(n + r - 1, r);
}

/**
 * @note O(r)
 */
template <int32_t MOD>
mint<MOD> simple_choose(int64_t n, int32_t r) {
    assert (0 <= r and r <= n);
    mint<MOD> num = 1;
    mint<MOD> den = 1;
    REP (i, r) {
        num *= n - i;
        den *= i + 1;
    }
    return num / den;
}
#line 6 "main.cpp"
using namespace std;
template <typename T> istream & operator >> (istream & in, vector<T> & xs) { REP (i, xs.size()) { in >> xs[i]; } return in; }

constexpr int MOD = 1e9 + 7;
mint<MOD> solve(int n, const vector<int> & x) {
    mint<MOD> ans = 0;
/*
    // O(n^2)
    REP (r, n) REP (l, r) {  // [l, r]
        int a = r - l - 1;
        int b = n - r + l - 1;
        ans += choose<MOD>(n - 1, a + 1 + (r != n - 1)) * fact<MOD>(a) * fact<MOD>(b - (r != n - 1)) * (x[r] - x[l]);
    }
*/
/*
    REP (r, n - 1) REP (l, r) {  // [l, r]
        ans += choose<MOD>(n - 1, r - l + 1) * fact<MOD>(r - l - 1) * fact<MOD>(n - r + l - 2) * x[r];
        ans -= choose<MOD>(n - 1, r - l + 1) * fact<MOD>(r - l - 1) * fact<MOD>(n - r + l - 2) * x[l];
    }
    int r = n - 1;
    REP (l, r) {  // [l, r]
        int a = r - l - 1;
        int b = n - r + l - 1;
        ans += choose<MOD>(n - 1, a + 1) * fact<MOD>(a) * fact<MOD>(b) * (x[r] - x[l]);
    }
*/
    vector<mint<MOD> > k(n - 1);
    REP3 (len, 1, n - 1) {
        k[len] = k[len - 1] + choose<MOD>(n - 1, len + 1) * fact<MOD>(len - 1) * fact<MOD>(n - len - 2);
    }
    REP (i, n - 1) {
        ans += k[i] * x[i];
        ans -= k[n - i - 2] * x[i];
    }
    int r = n - 1;
    REP (l, r) {  // [l, r]
        int a = r - l - 1;
        int b = n - r + l - 1;
        ans += choose<MOD>(n - 1, a + 1) * fact<MOD>(a) * fact<MOD>(b) * (x[r] - x[l]);
    }
    return ans;
}

int main() {
    int n; cin >> n;
    vector<int> x(n); cin >> x;
    cout << solve(n, x) << endl;
    return 0;
}


Measured memory_bytes: 2168