#define _CRT_SECURE_NO_WARNINGS
#include <assert.h>

#include <algorithm>
#include <array>
#include <chrono>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <optional>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <thread>
#include <unordered_map>
#include <unordered_set>
#include <variant>
#include <vector>

using namespace std;

const long long MOD = 1400305337;
const long long MOD2 = 1e9 + 9;
vector<int> a;
int n;
int mex[5001][5001];
unordered_set<int> v[5005];
int ans = 0;
void solve(int i, int prev) {
  ans = max(ans, prev);
  if (i == n) return;
  if (v[i].count(prev)) return;
  v[i].insert(prev);
  for (int j = 0; j + i < n; ++j) {
    solve(i + j + 1, prev);
    solve(i + j + 1, prev ^ mex[i][i + j]);
  }
}

signed main(int64_t argc, char** argv) {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t;
  cin >> t;
  while (t--) {
    cin >> n;
    a.resize(n);
    for (auto& e : a) cin >> e;
    for (int i = 0; i < n; ++i) v[i].clear();
    for (int i = 0; i < n; ++i) {
      set<int> x;
      for (int j = 0; j <= n + 1; ++j) x.insert(j);
      for (int j = i; j < n; ++j) {
        x.erase(a[j]);
        mex[i][j] = *x.begin();
      }
    }
    ans = 0;
    solve(0, 0);
    cout << ans << "\n";
  }
}