#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
typedef long long ll;
const int mod=1000000007;
const int M=200010;
int cas,n,a[M],A[M];
ll jie[M],inv[M];
ll C(int n,int m){
    return jie[n]*inv[m]%mod*inv[n-m]%mod;
}
int main(){
    jie[0]=1;inv[0]=inv[1]=1;
    for (int i=1;i<=200000;i++)jie[i]=jie[i-1]*i%mod;
    for (int i=2;i<=200000;i++)inv[i]=inv[mod%i]*(mod-mod/i)%mod;
    for (int i=2;i<=200000;i++)inv[i]=inv[i]*inv[i-1]%mod;
    scanf("%d",&cas);
    while (cas--){
        scanf("%d",&n);
        int flag=0,cnt=0;
        ll ans=1;
        for (int i=1;i<=2*n;i++)scanf("%d",&a[i]);
        int tmp=1;
        for (int i=2;i<=2*n;i++){
            if (a[i]==a[i-1])tmp++;
                else{
                    A[++cnt]=tmp;
                    tmp=1;
                }
        }
        A[++cnt]=tmp;
        for (int i=1;i<=cnt;i++){
            if (!flag){
                if (A[i]%2==1)ans=ans*2*C(A[i],A[i]/2)%mod;
                    else ans=ans*C(A[i],A[i]/2)%mod;
            }else{
                if (A[i]%2==1)ans=ans*C(A[i],A[i]/2)%mod;
                    else ans=ans*(C(A[i],A[i]/2)+C(A[i],A[i]/2-1))%mod;
            }
            if (A[i]%2==1)flag^=1;
        }
        printf("%I64d\n",ans);
    }
}