#include<bits/stdc++.h>
using namespace std;
int T,n;
int flag = 0;
int a[10010];
int main()
{
    freopen("sequence.in","r",stdin);
    freopen("sequence.out","w",stdout);
    scanf("%d", &T);
    for(int i = 1;i <= T; ++i)
    {
        flag = 0;
        scanf("%d", &n);
         for(int j = 1;j <= n; ++j)
        {
            scanf("%d", &a[j]);
        }
        for(int j = 2;j < n; ++j)
        {
            for(int p = 1;p < j; ++p)
            {
                for(int q = n;q > j; --q)
                {
                    if(a[q] - a[j] == a[j] - a[p])
                    {
                        cout<<"Y"<<endl;
                        flag = 1;
                        break;
                    }   
                }
                if(flag == 1)
                {
                    break;
                }   
            }
            if(flag == 1)
            {
                break;
            } 
        }
        if(flag == 0)
        {
        cout<<"N"<<endl;     
        }
    }   
}