#include <iostream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <algorithm>
#include <utility>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <queue>
#define rf freopen("in.in", "r", stdin)
#define wf freopen("out.out", "w", stdout)
#define rep(i, s, n) for(int i=int(s); i<=int(n); ++i)
using namespace std;
const int mx = 1e5 + 10, mod = 1e9+7;

int n, t;
int a[mx];
int suffix[mx];

int main()
{
	//rf;// wf;
	ios::sync_with_stdio(0);

	cin >> t;
	while(t--)
	{
		cin >> n;
		n++;

		for(int i = 1; i<=n; ++i)
			cin >> a[i];

		int power_of_2 = 1;
		for(int i = n; i >= 1; --i)
		{
			suffix[i] = (1ll * a[i] * power_of_2) % mod;
			
			if(i < n)
				suffix[i] = (suffix[i+1] + suffix[i]) % mod;

			power_of_2 = (power_of_2 * 2) % mod;
		}

		int ans = 0;
		power_of_2 = 1;

		for(int i = 1; i<n; ++i)
		{
			int count_ways = (1ll * power_of_2 * a[i]) % mod;
			count_ways = (1ll * count_ways * suffix[i+1]) %mod;

			ans = (ans + count_ways) % mod;
			
			if(i >= 2)
				power_of_2 = (power_of_2 * 2) % mod;
		}

		cout << (2*ans) % mod << '\n';
	}
	return 0;
}