// #define DEBUGGING
#include <bits/stdc++.h>
#define endl '\n'
#define ALL(V) (V).begin(), (V).end()
#define ALLR(V) (V).rbegin(), (V).rend()
using ll = std::int64_t;
using ull = std::uint64_t;
using PLL = std::pair<ll, ll>;
using TLL = std::tuple<ll, ll, ll>;
template <typename T> using V = std::vector<T>;
template <typename T> using VV = V<V<T>>;
template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename T, typename... Tail> const T& var_min(const T &t, const Tail&... tail) { return std::min(t, var_min(tail...)); }
template <typename T, typename... Tail> const T& var_max(const T &t, const Tail&... tail) { return std::max(t, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }
template <typename T> const T& clamp(const T &t, const T &low, const T &high) { return std::max(low, std::min(high, t)); }
template <typename T> void chclamp(T &t, const T &low, const T &high) { return t = clamp(t, low, high); }
namespace init__ { struct InitIO { InitIO() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << std::fixed << std::setprecision(30); } } init_io; }
#define mv_rec make_v(init, tail...)
template <typename T> T make_v(T init) { return init; }
template <typename T, typename... Tail> auto make_v(T init, size_t s, Tail... tail) { return V<decltype(mv_rec)>(s, mv_rec); }
#undef mv_rec
using namespace std;

#ifdef DEBUGGING
#include "../../debug/debug.cpp"
#else
#define DEBUG(...) 0
#define DEBUG_SEPARATOR_LINE 0
#endif

template <ll MOD>
class Combination {
private:
    ll N;
    V<ll> factv, ifactv;

public:
    Combination<MOD>(ll N) : N(N), factv(N + 1, 1), ifactv(N + 1) {
        for(ll i = 1; i <= N; i++) factv[i] = factv[i - 1] * i % MOD;
        ifactv.back() = inv(factv.back());
        for(ll i = N - 1; 0 <= i; i--) ifactv[i] = (i + 1) * ifactv[i + 1] % MOD;
    }

    ll fact(ll n) { return 0 <= n ? factv[n] : 0; }

    ll ifact(ll n) { return ifactv[n]; }

    ll pow(ll a, ll b) { return b ? (b & 1 ? a : 1) * pow(a * a % MOD, b / 2) % MOD : 1; }

    ll inv(ll a) { return pow(a, MOD - 2); }

    ll comb(ll n, ll k) { return factv[n] * ifactv[n - k] % MOD * ifactv[k] % MOD; }
};

const ll mod = 1e9 + 7;
Combination<mod> C(1e6);

int main() {
    ll N;
    cin >> N;
    V<ll> X(N);
    for (ll &e : X) cin >> e;
    V<ll> sum(N + 1), rsum(N + 1);
    for (ll i = 0; i < N; i++) sum[i + 1] = sum[i] + X[i];
    for (ll i = 0; i < N; i++) rsum[i + 1] = rsum[i] + X[N - 1 - i];

    ll ans = 0;
    for (ll len = 2; len <= N; len++) {
        ll rest = N - (len - 1);
        ll left = sum[rest];
        ll right = rsum[rest];
        ll dsum = right - left;
        ll last = X[N - 1] - X[N - 1 - (len - 1)];
        dsum -= last;
        {
            ll perm = 1;
            (perm *= C.fact(len - 2)) %= mod;
            (perm *= C.fact(N - 1 - len)) %= mod;
            (perm *= C.comb(N - 1, len)) %= mod;
            DEBUG(make_tuple(perm, dsum));
            ans += perm * dsum % mod;
        }
        {
            ll perm = 1;
            (perm *= C.fact(len - 2)) %= mod;
            (perm *= C.fact(N - len)) %= mod;
            (perm *= C.comb(N - 1, len - 1)) %= mod;
            DEBUG(make_tuple(perm, dsum, last));
            ans += perm * last % mod;
        }
    }

    cout << ans % mod << endl;
    return 0;
}
