#include <bits/stdc++.h>

using namespace std;

const int N = 1e5+10, Mod = 1e9+7;
long long pre[N], _pow[N];

int main()
{
	int n;
	cin >> n;
	
	_pow[0] = 1, pre[0] = 1;
	for(int i = 1; i <= n; i ++)
	{
		int a;
		scanf("%d", &a);
		pre[i] = pre[i - 1] * a % Mod;
		_pow[i] = _pow[i - 1] * 3 % Mod;
	}
	
	long long res = 0;
	for(int k = 1; k < n; k++)
	{
		res = (res + (pre[k] * 2 * _pow[n - k - 1]) % Mod) % Mod;
	}
	
	res = (res + pre[n] % Mod) % Mod;
	
	cout << res;
 }