#include<cstdio>
#include<algorithm>
#include<cstring>
#define mo 1000000007
using namespace std;
typedef long long ll;
ll inv[2000010],fac[2000010];
int a[200010],c[200010];
int read()
{
    int ans=0;
    char ch=getchar();
    while (ch<'0'||ch>'9') ch=getchar();
    while (ch>='0'&&ch<='9') ans=ans*10+ch-'0',ch=getchar();
    return ans;
}
ll C(int n,int m)
{
    if (n<m||m<0) return 0;
    return fac[n]*inv[m]%mo*inv[n-m]%mo;
}
int main()
{
    int cas;
    scanf("%d",&cas);
    fac[0]=1;
    for (int i=1;i<=200000;i++)
        fac[i]=fac[i-1]*i%mo;
    inv[1]=inv[0]=1;
    for (int i=2;i<=200000;i++)
        inv[i]=inv[mo%i]*(mo-mo/i)%mo;
    for (int i=2;i<=200000;i++)
        inv[i]=inv[i-1]*inv[i]%mo;
    while (cas--)
    {
        int n=read();
        for (int i=1;i<=n+n;i++) a[i]=read();
        for (int i=1;i<=n+n;i++) c[i]=0;
        int now=1;
        c[now]=1;
        for (int i=2;i<=n+n;i++) 
            if (a[i]==a[i-1]) c[now]++;
            else now++,c[now]=1;
        long long ans=1;
        int pre=0;
        for (int i=1;i<=now;i++)
        {
            if (pre&1)
            {
                if (c[i]%2==0)
                {
                    (ans*=C(c[i]+1,c[i]/2))%=mo;
                }
                else
                {
                    (ans*=C(c[i]+1,(c[i]+1)/2))%=mo;
                }
            }
            else
                (ans*=C(c[i],c[i]/2))%=mo;
            pre+=c[i];
        }
        printf("%lld\n",ans);
    }
    return 0;
}