#include <bits/stdc++.h>
using namespace std;
 
#define REP(i, n) for (ll i = 0; i < n; i++)
#define REPR(i, n) for (ll i = n; i >= 0; i--)
#define FOR(i, m, n) for (ll i = m; i < n; i++)
#define FORR(i, m, n) for (ll i = m; i >= n; i--)
#define REPO(i, n) for (ll i = 1; i <= n; i++)
#define ll long long
#define INF (ll)1 << 60
#define MINF (-1 * INF)
#define ALL(n) n.begin(), n.end()
#define MOD 1000000007
#define P pair<ll, ll>

ll powmod(ll a, ll b) {
    a %= MOD;
    ll res = 1;
    while (b > 0) {
        if (b % 2 == 1)res = res * a % MOD;
        a = a * a % MOD;
        b /= 2;
    }
    return res;
}
ll f[210000];
void cominit() {
    f[0] = 1;
    REP(i, 200000)f[i + 1] = f[i] * (i + 1) % MOD;
}

ll nCr(ll n, ll r) {
    if (n < r)return 0;
    if (n < 0 or r < 0)return 0;
    return f[n] * powmod(f[r] * f[n - r], MOD - 2) % MOD;
}

ll nPr(ll n, ll r) {
    if (n < r)return 0;
    if (n < 0 or r < 0)return 0;
    return f[n] * powmod(f[n - r], MOD - 2) % MOD;
}

ll nHr(ll n, ll r) {
    if (n < r)return 0;
    if (n < 0 or r < 0)return 0;
    return nCr(n + r - 1, r);
}
int main() {
    cominit();
    ll n;
    cin >> n;
    vector<ll> s(n);
    REP(i, n){
        cin >> s[i];
    }
    ll ans = 0;
    REP(i, n){
        ans += s[i] * nCr(n - 1, i) % MOD;
        ans %= MOD;
    }
    cout << ans << endl;
}