#include <bits/stdc++.h>
#define rep(i, l, r) for (int i = (l); i < (r); i++)
using namespace std;

typedef long long ll;

int main() {
    int N;
    cin >> N;
    vector<ll> A(N), P(N + 1, 1), T(N + 1, 1);
    rep(i, 0, N) cin >> A[i];
    ll MOD = 1000000007, ans = 0;
    rep(i, 0, N) P[i + 1] = P[i] * A[i] % MOD;
    rep(i, 0, N) T[i + 1] = T[i] * 3 % MOD;
    rep(i, 0, N - 1) ans = (ans + P[i + 1] * 2 % MOD * T[N - 2 - i] % MOD) % MOD;
    ans = (ans + P[N]) % MOD;
    cout << ans << endl;
    //rep(i, 0, N) cout << P[i + 1] << " "; cout << endl;
}