#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

const int mod = 1e9 + 7, N = 1e6 + 10;

int n;
ll a[N],sum[N];

ll qmi(int a,int k)
{
    ll sum = 1;
    while(k)
    {
        if(k & 1) sum = sum * a % mod;
        a = a * a % mod;
        k >>= 1; 
    }
    return sum % mod;
}

int main()
{
    scanf("%d",&n);
    for(int i = 0;i < n;i ++ ) scanf("%lld",&a[i]);
    sum[0] = a[0];
    for(int i = 1;i < n;i ++ ) sum[i] = (sum[i - 1] % mod * a[i] % mod) % mod;
    ll ans = 0;
    for(int i = 0;i < n;i ++ )
    {
        if(i != n - 1)
        {
            ans %= mod;
            ans += (sum[i] % mod * 2ll % mod * qmi(3,n - i - 2) % mod) % mod;
            ans %= mod;
        }
        else
        {
            ans %= mod;
            ans += sum[i] % mod;
            ans %= mod;
        }
    }
    printf("%lld\n",ans);
    return 0;
}