#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> P;
int INF = 3e18+7;
int mod = 1e9+7;
int dx[] = {1, 0,-1, 0, 1, 1,-1,-1};
int dy[] = {0, 1, 0,-1, 1,-1, 1,-1};
signed main() {
    int T;
    cin >> T;
    while (T--) {
        int N;
        cin >> N;
        vector<int>A(N);
        int sum = 0;
        for(int i = 0; i < N; i++) {
            cin >> A[i];
            sum += A[i];
        }
        for(int i = 0; i < N; i++) {
            for(int j = i+1; j < N; j++) {
                sum += A[i]*A[j];
            }
        }
        cout << sum << endl;
    }
}