#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++)
        ans = max(ans, mx | cnt[i]);
    vector<tuple<int, int, int>> Q;
    int mask = (1 << lg + 1) - 1;
    vector<vector<int>> pos(n);
    for (int i = 0; i < n; i++)
        pos[a[i]].push_back(i);
    for (int i = lg; ~i; i--)
    {
        if (ans >> i & 1)
            continue;
        for (int j = 0; j < n; j++)
        {
            for (int k = i + 1; k <= lg; k++)
            {
                if (cnt[j] >> k & 1)
                {
                    int val = cnt[j];
                    val -= 1 << k;
                    val |= (1 << i + 1) - 1;
                    for (int i = 0; i + val <= pos[j].size(); i++)
                    {
                        int l = i == 0 ? 0 : pos[j][i - 1] + 1;
                        int r = i + val < pos[j].size() ? pos[j][i + val] - 1 : n - 1;
                        Q.emplace_back(l, r, val);
                    }
                    break;
                }
            }
        }
        break;
    };
    int B = sqrt(n);
    sort(all(Q), [&](auto a, auto b)
         {
        auto [l1,r1,w1]=a;
        auto [l2,r2,w2]=b;
        if(l1/B!=l2/B)return l1/B>l2/B;
        else return r1/B<r2/B; });
    int L = 0, R = 0;
    vector<int> mcnt(n);
    priority_queue<pair<int, int>> q;
    auto oo = [&](int val)
    {
        while (mcnt[q.top().second] != q.top().first)
            q.pop();
        int x = q.top().first;
        ans = max(ans, x | val);
    };
    auto add = [&](int p)
    {
        mcnt[p]++;
        q.push({mcnt[p], p});
    };
    auto del = [&](int p)
    {
        mcnt[p]--;
        q.push({mcnt[p], p});
    };
    for (auto [l, r, val] : Q)
    {
        while (R <= r)
            add(a[R++]);
        while (R - 1 > r)
            del(a[--R]);

        while (L + 1 < l)
            del(a[L++]);
        while (L > l)
            add(--L);

        oo(val);
    }
    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();
}