#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll N = 2e5 + 10;
const ll MOD = 1e9 + 7;

int n, ans = 0;

void max_gcd(int ind, vector<int> &v, int gc, int gc2, int cnt) {
  if(ind == n) {
    if(cnt == (n + 1) / 2) {
      ans = max(ans, gc + gc2);
    }
    return;
  }
  int a = gcd(gc, v[ind]);
  int b = gcd(gc2, v[ind]);
  max_gcd(ind + 1, v, a, gc2, cnt + 1);
  max_gcd(ind + 1, v, gc, b, cnt);
}

void solve()
{
  cin >> n;
  
  vector<int> v(n);
  for(int i = 0; i < n; i++) {
    cin >> v[i];
  }
  ans = 0;
  max_gcd(0, v, 0, 0, 0);
  cout << ans << "\n";
}

int main()
{
  ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);

  int t;
  cin >> t;
  while(t--){
    solve();
  }
}