#include <bits/stdc++.h>
using namespace std;
void make_unique(vector<long long> vec) {
  sort((vec).begin(), (vec).end());
  vec.resize(unique((vec).begin(), (vec).end()) - vec.begin());
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int t;
  cin >> t;
  while (t--) {
    long long k, n, m, i, j, flag = 0, count = 0, move = 0;
    string s;
    cin >> n;
    long long A[n];
    vector<long long> v;
    for (i = 0; i < n; i++) cin >> A[i];
    long long freq[51] = {0};
    for (i = 0; i < n; i++) {
      freq[A[i]]++;
    }
    long long maxf = freq[0];
    long long pos = 0;
    vector<long long> sum(105, 0);
    for (i = 0; i <= n; i++) {
      for (j = i; j <= n; j++) {
        if (i == j)
          sum[i + j] += freq[i] / 2;
        else {
          sum[i + j] += min(freq[i], freq[j]);
        }
      }
    }
    cout << *max_element((sum).begin(), (sum).end()) << endl;
  }
  return 0;
}
