#include<bits/stdc++.h>
using namespace std;
const int MAX_N=5+2e5,MOD=1e9+7;
int a[MAX_N],b[MAX_N],top;
int fac[MAX_N],inv[MAX_N],fac_inv[MAX_N];
void init(int n){
    fac[0]=fac_inv[0]=inv[1]=1;
    for(int i=1;i<=n;++i){
        fac[i]=1ll*fac[i-1]*i%MOD;
        if(i>1)inv[i]=1ll*(MOD-MOD/i)*inv[MOD%i]%MOD;
        fac_inv[i]=1ll*fac_inv[i-1]*inv[i]%MOD;
    }
}
int c(int n,int m){
    return 1ll*fac[n]*fac_inv[m]%MOD*fac_inv[n-m]%MOD;
}
int main(){
//    freopen("1.in","r",stdin);
//    freopen("1.out","w",stdout);
    init(2e5);
    int T; scanf("%d",&T);
    while(T--){
        top=0;
        int n; scanf("%d",&n);
        for(int i=1;i<=n+n;++i) scanf("%d",&a[i]);
        sort(a+1,a+n+n+1);
        a[n+n+1]=-100;
        int last=0;
        for(int i=1;i<=n+n;++i)
            if(a[i]!=a[i+1]) b[++top]=i-last,last=i;
        int ans=1,sum=0;
        for(int i=1;i<=top;++i){
            if(sum&1){
                if(b[i]&1)
                    ans=2ll*ans*c(b[i],b[i]>>1)%MOD;
                else
                    ans=1ll*ans*(c(b[i],b[i]>>1)+c(b[i],(b[i]>>1)+1))%MOD;
            }else{
                ans=1ll*ans*c(b[i],b[i]>>1)%MOD;
            }
            sum+=b[i];
    //        printf("(%d)",ans);
        }
        printf("%d\n",ans);
    }
    return 0;
}