#include <bits/stdc++.h>
using namespace std;
long long t = 1, T;
void print2d(vector<vector<long long>> &v) {
  for (long long i = 0; i < v.size(); i++) {
    for (long long x : v[i]) {
      cout << x << ' ';
    }
    cout << '\n';
  }
}
void print(vector<long long> &a) {
  for (long long x : a) {
    cout << x << ' ';
  }
  cout << '\n';
  return;
}
long long fun(long long x, long long y) { return x * x + y * y; }
void solve() {
  long long n;
  cin >> n;
  vector<long long> a(n, 0);
  vector<long long> freq(n + 1, 0);
  long long x;
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
    freq[a[i]]++;
  }
  set<long long> v;
  for (long long i = 0; i < n; i++) {
    for (long long j = i + 1; j < n; j++) {
      v.insert(a[i] + a[j]);
    }
  }
  long long ans = 0;
  for (long long sum : v) {
    long long i, j;
    if (sum & 1) {
      i = sum / 2;
      j = i + 1;
    } else
      i = j = sum / 2;
    long long rep = 0;
    while (i >= 1 && j <= n) {
      if (i == j) {
        rep += freq[i] / 2;
        i--;
        j++;
      } else {
        rep += min(freq[i], freq[j]);
        i--;
        j++;
      }
    }
    ans = max(ans, rep);
  }
  cout << ans << '\n';
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> t;
  T = t;
  while (t--) {
    solve();
  }
  return 0;
}
