#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int maxn = 200005;
const LL mod = 1000000007;
int T, n, a[maxn];
map<int, int> S;
LL fac[maxn], ans;
LL quickpow(LL x, LL b) {
    LL ans = 1;
    while (b) {
        if (b & 1ll) (ans *= x) %= mod;
        (x *= x) %= mod;
        b >>= 1;
    }
    return ans;
}
LL inv(LL x) {
    return quickpow(x, mod - 2);
}
LL C(int n, int m) {
    return fac[n] * inv(fac[m]) % mod * inv(fac[n - m]) % mod;
}
int main() {
    fac[0] = fac[1] = 1;
    for (int i = 2; i < maxn; ++i) {
        fac[i] = fac[i - 1] * i % mod;
    }
    for (scanf("%d", &T); T--; ) {
        scanf("%d", &n);
        S.clear();
        for (int i = 1, x; i <= 2 * n; ++i) {
            scanf("%d", &x);
            if (!S.count(x)) S[x] = 1;
            else ++S[x];
        }
        LL ans = 1;
        int tot = 0;
        for (map<int, int>::iterator iter = S.begin(); iter != S.end(); ++iter) {
            int x = iter->second;
            if (tot % 2 == 0) {
                (ans *= C(x, x / 2)) %= mod;
                if (x % 2 == 1) (ans <<= 1) %= mod;
            } else {
                if (x % 2 == 1) {
                    (ans *= C(x, x / 2)) %= mod;
                } else {
                    (ans *= ((C(x, x / 2 + 1) + C(x, x / 2)) % mod)) %= mod;
                }
            }

            tot += iter->second;
        }
        cout << ans << endl;
    }
    return 0;
}