/*
 *
 ********************************************************************************************
 * AUTHOR : Vijju123                                                                        *
 * Language: C++14                                                                          *
 * Purpose: -                                                                               *
 * IDE used: Codechef IDE.                                                                  *
 ********************************************************************************************
 *
 Comments will be included in practice problems if it helps ^^
 */
 
 
 
#include <iostream>
#include<bits/stdc++.h>
using namespace std;
 
int main() {
	// your code goes here
	#ifdef JUDGE
    freopen("input.txt", "rt", stdin);
    freopen("output.txt", "wt", stdout);
    #endif
	ios_base::sync_with_stdio(0);
	cin.tie(NULL);
	cout.tie(NULL);
	int t;
	cin>>t;
	assert(t>=1 and t<=10);
	while(t--)
	{
	    int n;
	    cin>>n;
	    assert(n>=1 and n<=100000);
	    int arr[n];
	    int freq[2500]={0};
	    for(int i=0;i<n;i++)
	    {
	        cin>>arr[i];
	        assert(-1000<=arr[i] and arr[i]<=1000);
	        arr[i]+=1000;//Make numbers non-negative
	        freq[arr[i]]++;
	    }
	    int i,j;
	    long long ans=0;
	    for(i=0;i<=2000;i++)
	    {
	        for(j=0;j<=2000;j++)
	        {//Check for all pairs (a,b)
	            if((i+j)%2==0 and freq[(i+j)/2] and freq[i] and freq[j])
	            {
	                if(i!=j)
	                    ans+=1LL*freq[i]*freq[j];
	                else
	                    ans+=1LL*(freq[i]-1)*freq[j];//Formulas as discussed in editorial.
	            }
	        }
	    }
	    ans>>=1;
	    cout<<ans<<endl;
	    
	   
	    
	}
	
	return 0;
}