#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define int long long
const int mod = 1e9 + 7;
#define all(x) x.begin(), x.end()
int qp(int a, int b)
{
    int res = 1;
    while (b)
    {
        if (b & 1)
            res = res * a % mod;
        a = a * a % mod;
        b >>= 1;
    }
    return res;
};
void solve()
{
    int n;
    cin >> n;
    vector<int> a(n);
    vector<int> cnt(n);
    for (int i = 0; i < n; i++)
        cin >> a[i], a[i]--, cnt[a[i]]++;
    int c = max_element(all(cnt)) - cnt.begin();
    int mx = cnt[c];
    int lg = __lg(mx);
    int ans = mx;
    for (int i = 0; i < n; i++)
    {
        if (i == c)
            continue;
        ans = max(ans, mx | cnt[i]);
        for (int j = lg; j >= 0; j++)
        {
            if (cnt[i] >> j & 1)
            {
                if (mx >> j & 1)
                {
                    int g = cnt[i] - (1 << j);
                    g |= (1 << j) - 1;
                    ans = max(ans, g | mx);
                }
            }
        }
    }
    // 选1个mx再选一个谁
    // 选一个能补高位的，
    cout << ans << endl;
    return;
}
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int T = 1;
    cin >> T;
    while (T--)
        solve();
}