#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main(){
    int t, n, tp, i, j, k, l;
    vector<int> a;
    vector<long long> x, xmin;

    cin >> t;

    for (i=0; i<t; i++){
        cin >> n;
        a.clear();

        for(j=0; j<n; j++){
            cin >> tp;
            a.push_back(tp);
        }

        for(j=0; j<n-1; j++){
            x.clear();
            l = 0;
            for(k=j+1; k<n; k++){
                x.push_back((long long)a[j] * a[k]);
                if (l != 0 && x[l-1] < x[l]) break;
                l++;
            }

            xmin.push_back(*min_element(x.begin(), x.end()));
        }

        cout << *max_element(xmin.begin(), xmin.end()) << "\n";
        xmin.clear();
    }

}