#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5, mod = 1e9 + 7;
int t, n, a[maxn + 10], b[maxn + 10], m;
int f[maxn + 10][3];
int fac[maxn + 10], inv[maxn + 10], ifac[maxn + 10];

inline void addto(int &x, int y) {
    x += y; if (x >= mod) x -= mod;
}
inline int dec(int x, int y) {
    x -= y; return x < 0 ? x + mod : x;
}
inline int mul(int x, int y) {
    return 1ll * x * y % mod;
}

void pre() {
    fac[0] = ifac[0] = 1;
    for (int i = 1; i <= maxn; ++i) {
        fac[i] = mul(fac[i - 1], i);
        inv[i] = i == 1 ? 1 : dec(0, mul(mod / i, inv[mod % i]));
        ifac[i] = mul(ifac[i - 1], inv[i]);
    }
}

int comb(int x, int y) {
    return mul(fac[x], mul(ifac[y], ifac[x - y]));
}

int main() {
    pre();
    scanf("%d", &t);
    while (t--) {
        scanf("%d", &n);
        for (int i = 1; i <= n * 2; ++i) scanf("%d", &a[i]);
        sort(a + 1, a + n * 2 + 1);
        m = 0;
        for (int i = 1, lst; i <= n * 2; i = lst) {
            for (lst = i; lst <= n * 2 && a[lst] == a[i]; ++lst);
            ++m; b[m] = lst - i;
        }
        for (int i = 0; i <= m + 1; ++i)
            f[i][0] = f[i][1] = f[i][2] = 0;
        f[1][0] = 1;
        for (int i = 1; i <= m; ++i)
            for (int j = 0; j < 3; ++j) {
                int w = b[i] - !!j;
                if (w & 1) {
                    addto(f[i + 1][1], mul(f[i][j], comb(b[i], w / 2 + (j == 1))));
                    addto(f[i + 1][2], mul(f[i][j], comb(b[i], w / 2 + 1 + (j == 1))));
                } else {
                    addto(f[i + 1][0], mul(f[i][j], comb(b[i], w / 2 + (j == 1))));
                }
            }
        printf("%d\n", f[m + 1][0]);
    }
}