#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define lll __int128
// #define int ll
#define db double
#define pii pair<int,int>
#define fi first
#define se second
#define mp make_pair
using namespace std;
ll read(){
	ll sum=0,f=1;char st=getchar();
	while(st<'0'||st>'9'){
		if(st=='-')f=-1;
		st=getchar();
	}
	while('0'<=st&&st<='9'){
		sum=(sum<<3)+(sum<<1)+st-'0';
		st=getchar();
	}
	return sum*f;
}
const int maxn=100010;//maxm=600010;
int cnt[maxn];
signed main(){
	
	int TT=read();
	while(TT--){
		int n=read();
		for(int i=1;i<=n;++i){
			int x=read();
			++cnt[x];
		}
		int ma1=0,ma2=0;
		for(int i=1;i<=n;++i){
			if(cnt[i]>ma1)ma2=ma1,ma1=cnt[i];
			else ma2=max(ma2,cnt[i]);
		}
		for(int i=19;i>=0;--i){
			int op1=(ma1>>i)&1,op2=(ma2>>i)&1;
			if(!op1||!op2)continue;
			for(int j=i;j>=0;--j)ma1|=(1<<j);
			break;
		}
		printf("%d\n",ma1|ma2);
	}	
	
    return 0;
}