#include<bits/stdc++.h>
using namespace std;

#define LL long long
const int mx =2e5+5;
const long long mo = 1e9+7;
int a[mx];
long long dp[mx][3];
long long inv[mx];

void init()
{
    inv[0]=inv[1]=1;
    for (int i=2;i<mx/2;i++)
    {
        inv[i]=(mo-mo/i)*inv[mo%i]%mo;
    }
}

long long c(long long n,long long m)
{
    if (m==0) return 1;
    long long ans = 1;
    for (int i=1;i<=m;i++)
    {
        ans = ans*n%mo;
        n-=1;
        ans = ans*inv[i]%mo;
    }
    return ans;
}

int main()
{
    init();
    int t;
    cin>>t;
    while (t--)
    {
        int n;
        scanf("%d",&n);
        int cut = 0,p=0,w,k=-1;
        for (int i=0;i<2*n;i++)
        {
            scanf("%d",&w);
            if (w==k) cut++;
            else
            {
                if (cut!=0)
                {
                    a[p++]=cut;
                }
                cut=1;
                k = w;
            }
        }
        a[p++]=cut;
        if (a[0]%2==0)
        {
            dp[0][2]= c(a[0],a[0]/2);
            dp[0][0]=dp[0][1]=0;
        }
        else
        {
            dp[0][0]=dp[0][1]=c(a[0],a[0]/2);
            dp[0][2]=0;
        }
      //  cout<<dp[0][0]<<" "<<inv[1]<<endl;
        for (int i=1;i<p;i++)
        {
            if (a[i]%2==0)
            {
                if (dp[i-1][2]>0)
                {
                    dp[i][2]= dp[i-1][2]*c(a[i],a[i]/2)%mo;
                    dp[i][0]=dp[i][1]=0;
                }
                else
                {
                  dp[i][1]=  dp[i][0] = (dp[i-1][0]*c(a[i],a[i]/2) + dp[i-1][1]*c(a[i],a[i]/2-1))%mo;
                  dp[i][2]=0;
                   // dp[i][1] = (dp[i-1][1]*c(a[i],a[i]/2)%mo + dp[i-1][0]*c(a[i],a[i]/2-1)%mo)%mo;
                }

            }
            else
            {
                if (dp[i-1][2]>0)
                {
                    dp[i][0]=dp[i][1]=dp[i-1][2]*c(a[i],a[i]/2)%mo;
                    dp[i][2]=0;
                }
                else
                {
                    dp[i][2]= 2*dp[i-1][0]*c(a[i],a[i]/2) %mo;
                    dp[i][0]=dp[i][1]=0;
                   // cout<<dp[i-1][0]<<endl;
                }
            }
        }
        cout<<dp[p-1][2]<<endl;
    }

}