// WA mod とり忘れ
#include <iostream>
#include <vector>
using namespace std;
#include <atcoder/modint>
using mint = atcoder::modint1000000007;

int main() {
    int N;
    cin >> N;
    long long ret = 0;
    mint prod = 1;

    const mint d23 = mint(2) / 3;
    for (int i = 0; i < N; i++) {
        ret = (mint(ret) * 3).val();
        int a;
        cin >> a;
        prod *= mint(a);
        ret = (mint(ret) + (prod * d23)).val();
    }
    ret += (prod / 3).val();
    cout << ret << '\n';
}