#include<stdio.h>
#include<cmath>
#include<algorithm>
#include<iostream>
#include<set>
#include<map>
#include<cstring>
#include<string>
#include<queue>
using namespace std;
typedef long long ll;
const int maxn = 2e5+5;
const ll mod = 1e9+7;
long long dp[maxn][3];
//const long long mod = 1000000009;
long long inv[maxn];
long long ba[maxn];
long long rba[maxn];
#define M 200001
void pre() {
    inv[0] = inv[1] = 1;
    ba[0] = ba[1] = 1;
    rba[0] = rba[1] = 1;
    for (int i = 2; i < M; i++) {
        inv[i] = ((mod - mod / i) * inv[mod % i]) % mod;
        ba[i] = (ba[i - 1] * i) % mod;
        rba[i] = (rba[i - 1] * inv[i]) % mod;
    }
}
long long C(int n, int k) {
    return (ba[n] * rba[k] % mod ) * rba[n - k] % mod;
}
int main() {
    int T;
    pre();
    scanf("%d", &T);
    for (int tt = 0; tt < T; ++tt) {
        int n;
        scanf("%d",&n);
        vector<int> vec;
        int last = -1 , cnt = 1;
        for (int i=0;i<2*n;i++) {
            int a;
            scanf("%d",&a);
            if (a == last) {
                cnt++;
            } else {
                last = a;
                vec.push_back(cnt);
                cnt = 1;
            }
        }
        vec.push_back(cnt);
        if(n>1e4) {
            memset(dp,0, sizeof(dp));
        } else {
            for (int i=0;i<vec.size();++i){
                for (int j=0;j<3;j++)
                dp[i][j]=0;
            }
        }
        dp[0][0]=1;
        for (int i=1;i<vec.size();++i) {
           // cout << i<< " "<<vec[i]<<endl;
            int now = vec[i];
            for (int j=0;j<3;j++) {
                if (dp[i-1][j] == 0) continue;
                if (j==0) {
                    if (now%2) {
                        dp[i][1] += (dp[i-1][j] * C(now,now/2+1))%mod;
                        dp[i][2] += (dp[i-1][j] * C(now,now/2))%mod;
                    } else {
                        dp[i][0] += (dp[i-1][j] * C(now,now/2))%mod;
                    }
                } else if (j==1) {
                    if (now%2) {
                        dp[i][0] += (dp[i-1][j] * C(now, now/2))%mod;
                    } else {
                        dp[i][1] += (dp[i-1][j] * C(now,now/2))%mod;
                        dp[i][2] += (dp[i-1][j] * C(now,now/2-1))%mod;
                    }
                } else if (j==2) {
                    if (now%2) {
                        dp[i][0] += (dp[i-1][j] * C(now, now/2+1))%mod;
                    } else {
                        dp[i][1] += (dp[i-1][j] * C(now,now/2+1))%mod;
                        dp[i][2] += (dp[i-1][j] * C(now,now/2))%mod;
                    }
                }
            }
        }
        printf("%I64d\n", dp[vec.size()-1][0]%mod);
    }
    return 0;
}