#include <bits/stdc++.h>

using namespace std;

const int N = 2016;
const int MOD = 1e9 + 7;
const int INV2 = 500000004;

int n;
int a[N];
int C[N][N];

void _main() {
    for (int i = 0; i < N; ++i) {
        C[i][0] = 1;
        for (int j = 1; j <= i; ++j) {
            C[i][j] = (C[i - 1][j] + C[i - 1][j - 1]) % MOD;
        }
    }

    int T; cin >> T;
    while (T--) {
        cin >> n;
        for (int i = 0; i < n; ++i) cin >> a[i];
         map<int, int> S;
        for (int i = 0; i < n; ++i) ++S[a[i]];
        int distincts = S.size();
        int repeat = 0;
        for (auto it : S) if (it.second == 2) repeat += 1;

        vector<long long> power (1, 1);
        for (int i = 1; i <= repeat; ++i)
            power.push_back(power.back() * INV2 % MOD);

        vector<long long> fact (1, 1);
        for (int i = 1; i <= n; ++i)
            fact.push_back(fact.back() * i % MOD);

        long long ans = fact[n] * power[repeat] % MOD;
        for (int i = 1; i <= repeat; ++i) {
            int n_pairs = i;
            int remain = n - n_pairs * 2;
            long long first = fact[n_pairs];
            long long second = fact[remain] * power[repeat - n_pairs] % MOD;
            long long cur = first * second % MOD;
            cur = cur * C[n_pairs + remain][n_pairs] % MOD;
            cur = cur * C[repeat][n_pairs] % MOD;

            if (i & 1) {
                ans -= cur;
            } else {
                ans += cur;
            }
            ans %= MOD;
            if (ans < 0) ans += MOD;
        }

        cout << ans << '\n';
    }
}

int main() {
    ios::sync_with_stdio(false); cin.tie(NULL);
    _main();
    cerr << setprecision(2) << fixed << endl << "Elapsed " << (double)clock() / CLOCKS_PER_SEC << endl;
    return 0;
}