#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int T;
    cin >> T;
    while(T--){
        int N;
        cin >> N;
        vector<int> A(N);
        int maxA = 0;
        for(int i = 0; i < N; i++){
            cin >> A[i];
            maxA = max(maxA, A[i]);
        }

        int kodd = (N + 1) / 2;
        int keven = N / 2;

        vector<int> freq(maxA+1, 0);
        for(int x : A) freq[x]++;

        // cnt[d] = number of elements divisible by d
        vector<int> cnt(maxA+1, 0);
        for(int d = 1; d <= maxA; d++){
            for(int m = d; m <= maxA; m += d)
                cnt[d] += freq[m];
        }

        // collect candidates
        vector<int> Xs, Ys;
        for(int d = 1; d <= maxA; d++){
            if(cnt[d] >= kodd)  Xs.push_back(d);
            if(cnt[d] >= keven) Ys.push_back(d);
        }

        ll best = 0;
        for(int X : Xs){
            for(int Y : Ys){
                ll L = lcm<ll>(X, Y);
                int inter = (L <= maxA ? cnt[L] : 0);
                int covered = cnt[X] + cnt[Y] - inter;
                if(covered == N){
                    best = max(best, (ll)X + Y);
                }
            }
        }
        cout << best << '\n';
    }
    return 0;
}