///**Bismillahir Rahmanir Raheem**
///**       Mizanul Hoque       **
///**           IIUC            **
/// ###############################
#include <bits/stdc++.h>
using namespace std;
/// POLICY BASED DATA STRUCTURE..
/// order_of_key return number of element which are strictly greater/smaller than x..
/// find_by_order return ans iterator corresponding to the xth position of the set..

// #include<ext/pb_ds/assoc_container.hpp>
//  #include<ext/pb_ds/tree_policy.hpp>
//  using namespace __gnu_pbds;
//  #define ordered_set tree<int, null_type,less_equal<int>, rb_tree_tag, tree_order_statistics_node_update>

#define faster                        \
    ios_base::sync_with_stdio(false); \
    cin.tie(NULL)

#define pb push_back
#define all(x) (x).begin(), (x).end()
#define allr(x) (x).rbegin(), (x).rend()
#define sz(n) (int)(n).size()
#define eps 1e-10

#define YES cout << "YES" << endl
#define NO cout << "NO" << endl
#define Yes cout << "Yes" << endl;
#define No cout << "No" << endl;
#define yes cout << "yes" << endl;
#define no cout << "no" << endl;

#define min3(a, b, c) min(c, min(a, b))
#define min4(a, b, c, d) min(d, min(c, min(a, b)))
#define max3(a, b, c) max(c, max(a, b))
#define max4(a, b, c, d) max(d, max(c, max(a, b)))

#define pi 2 * acos(0) /// acos(-1.0)
#define deg_to_rad(x) ((x) * ((2 * acos(0)) / 180.0))
#define rad_to_deg(x) ((x) * (180.0 / (2 * acos(0))))

#define fi first
#define sc second
#define mp make_pair
#define __lcm(a, b) (a / __gcd(a, b) * b*1LL)

typedef long long ll;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const int M = 1e9 + 7;
const int N = 200020;

// ll n,m,i,k,h;

vector<ll> prime_divisor[N];
int vis[N];
vector<int> edge[N];

bool cmp(pair<ll, ll> p1, pair<ll, ll> p2)
{
    return p1.fi < p2.fi;
}
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
inline ll gen_random(ll l, ll r)
{
    return uniform_int_distribution<ll>(l, r)(rng);
}

// gen_random(l, r); // generates a random integer between l and r

const int lim = 100005;
vector<int> divisors[lim];
void sieve()
{
    for (int i = 1; i < lim; i++)
    {
        for (int j = i; j < lim; j += i)
        {
            divisors[j].push_back(i);
        }
    }
}

int freq[lim]; // to count the frequency of each element
int tot[lim];  // tot[i]->gcd count of i

void solve()
{
    ll i, j, k, n, m, p, q, x, y, z, u, v, l, r, mod = 1e9 + 7, mx, mn, mx1, mn1, cnt1;
    cin >> n;
    ll a[n + 5];
    ll gc = 0;
    memset(freq, 0, sizeof(freq));
    memset(tot, 0, sizeof(tot));
    for (i = 0; i < n; i++)
    {
        cin >> a[i];
        gc = __gcd(gc, a[i]);
        freq[a[i]]++;
    }
    for (i = 1; i < lim; i++)
    {
        for (j = i; j < lim; j += i)
        {
            tot[i] += freq[j];
        }
    }
    int ans=2*gc;
    //assert(n > 0);
    for(k=0;k<3;k++)
    {
        int x=a[rng()%n];
        int y=a[rng()%n];
        for(int i: divisors[x])
        {
           for(int j: divisors[y])
           {
               if(i==j)continue;
               ll lc=(1LL*i*j)/__gcd(i,j);
               if(lc>=lim)lc=0;
               //assert(lc < lim);
               if(tot[i]+tot[j]-tot[lc]!=n)continue;
                p=tot[i];
                q=tot[j];
                if(p<q)swap(p,q);
                if(p>=(n+1)/2 && q>=(n/2))
                {
                    ans=max(ans,i+j);
                }
           }
        }
    }
    cout<<ans<<endl;
}

int main()
{
    faster;
    ll tc = 1;
    cin >> tc;
    sieve();
    for (ll t = 1; t <= tc; t++)
    {
        /// cout<<"Case "<<t<<": ";
        solve();
    }

    return 0;
}