#include <bits/stdc++.h>
using namespace std;
int t, n, max1, max2;
int a[100010];
int b[100010];
void clrb();
void doit()
{
    max1 = 100001, max2 = 100002;
    b[max1] = -1;
    b[max2] = -1;
    cin >> n;
    for (int i = 1; i <= n; ++i)
    {
        cin >> a[i];
        b[a[i]]++;
    }
    for (int i = 1; i <= n; ++i)
    {
        if (b[a[i]] > b[max1])
        {
            max2 = max1;
            max1 = a[i];
        }
        else if (b[a[i]] > b[max2])
        {
            max2 = a[i];
        }
    }
    if (max1 == max2)
    {
        cout << b[max1] << endl;
        clrb();
        return;
    }
    max1 = b[max1];
    max2 = b[max2];
    int ans = max(max1 | max2, max(max1 | max1, max2 | max2));
    int tmp1 = max1 & max2;
    int top = 21;
    for (int i = 20; i >= 0; --i)
    {
        if ((1 << i) & tmp1)
        {
            top = (1 << i) - 1;
            break;
        }
    }
    cout << (max1 | max2 | top) << endl;
    clrb();
}
void clrb()
{
    for (int i = 1; i <= n; ++i)
    {
        b[a[i]] = 0;
    }
}
signed main()
{
    cin >> t;
    while (t--)
    {
        doit();
    }
    return 0;
}