#include <bits/stdc++.h>
using namespace std;

int main()
{
	int N;
	cin >> N;
	vector<long long> A( N );
	for( int i = 0; i < N; i ++ ) cin >> A[i];

	const long long MOD = 1000000007;
	vector<long long> x3( N );
	x3[0] = 1;
	for( int i = 1; i < N; i++ ) x3[i] = x3[i - 1] * 3 % MOD;
	long long ans = 0;
	long long a = 1;
	for( int i = 0; i < N; i++ ) {
		a *= A[i];
		a %= MOD;
		long long aa = a;
		int n = max( N - 2 - i, 0 ); 
		aa *= x3[n];
		aa %= MOD;
		if( N - 1 - i > 0  ) aa *= 2;
		aa %= MOD;
		ans += aa;
		ans %= MOD;
	}

	cout << ans << endl;
}