#include <iostream>
#include <algorithm>
using namespace std;

const long long md = 1000000007;
long long c[200009], l[200009];

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n; cin >> n;
	l[0] = c[0] = 1;
	for (int i = 1; i <= n; i++) {
		int a; cin >> a;
		l[i] = (l[i - 1] * a) % md;
		c[i] = (c[i - 1] * 3) % md;
	}
	long long ans = l[n];
	for (int i = 1; i < n; i++) 
		ans = (ans + l[i] * c[n - i - 1] * 2) % md;
	cout << ans << '\n';
	return 0;
}