#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define IOS std::ios::sync_with_stdio(false); cin.tie(NULL);cout.tie(NULL);
#define endl "\n"

const ll N = 25;
const ll mod = 1e9+7;


void solve()
{
    ll n;
    cin>>n;

    vector<ll> cnt(n+10);
    for(int i=1;i<=n;i++){
        ll t;cin>>t;
        cnt[t]++;
    }
    
    set<ll> s;
    vector<ll> b;
    for(int i=1;i<=n;i++){
        s.insert(cnt[i]);
    }
    for(auto x:s){
        b.push_back(x);
    }

    ll ans = 0;    
    for(int i=0;i<b.size();i++){
        for(int j=0;j<b.size();j++){
            if((b[i]&b[j])==0){
                ans = max(ans,b[i]|b[j]);
            }       
            else{
                // ans = max(ans,b[i]|b[j]|((b[i]&b[j])-1));
                ll x = (b[i]&b[j]);
                for(int i=20;i>=0;i++){
                    if(x&(1<<i)){
                        ans = max(ans,b[i]|b[j]| ( (1<<(i+1))-1 ) );
                        break;
                    }
                }
            }
        }
    }
    
    
    
    cout<<ans<<endl;
}


int main()
{
    IOS;
    int T=1;cin>>T;
    while(T--){
        solve();
    }
    
    return 0;
}