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

#define pb push_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
typedef long long ll;
typedef pair<int,int> pii;
const int maxn = 2e5 + 70;
const int INF = 0x3f3f3f3f;
const ll inf = 0x3f3f3f3f3f3f3f3f;
const int MOD = 1e9 + 7;
const double eps = 1e-7;
const double PI = acos(-1.0);

int n, m, k;

ll fac[maxn], fac_inv[maxn];

void gcd(ll a, ll b, ll &d, ll &x, ll &y){
    if (!b){ d = a; x = 1; y = 0; }
    else{ gcd(b, a%b, d, y, x); y -= x*(a / b); }
}

ll inv(ll a, ll n){
    ll d, x, y;
    gcd(a, n, d, x, y);
    return d == 1 ? (x + n) % n : -1;
}

void get_fac(){
    fac[0] = 1;
    for (int i = 1; i < maxn; i++) fac[i] = (fac[i - 1] * i) % MOD;

    fac_inv[maxn - 1] = inv(fac[maxn - 1], MOD);
    for (int i = maxn - 2; i >= 0; i--){
        fac_inv[i] = (i + 1) * fac_inv[i + 1] % MOD;
    }
}

ll C_mod(ll n, ll m){
    return ((fac[n] * fac_inv[m] % MOD) * fac_inv[n - m]) % MOD;
}

int a[maxn];

int main(){
    //freopen("in.txt", "r", stdin);
    get_fac();
    int T;
    cin>>T;
    while(T--){
        scanf("%d",&n);
        n*=2;
        for(int i=1;i<=n;i++) scanf("%d",&a[i]);

        ll ans=1; int flag=0;
        for(int i=n,j=i;i>=1;i=j){
            while(j>=1 && a[j]==a[i]) j--;

            int x=i-j;
            if(!flag){
                if(x&1){
                    ans=ans*C_mod(x,x/2)*2%MOD;
                    flag=1;
                }
                else{
                    ans=ans*C_mod(x,x/2)%MOD;
                }
            }
            else{
                if(x&1){
                    ans=ans*C_mod(x,x/2)%MOD;
                    flag=0;
                }
                else{
                    ans=ans*(C_mod(x,x/2)+C_mod(x,x/2-1))%MOD;
                }
            }
        }
        printf("%d\n",(int)ans);
    }
    return 0;
}