#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cstdlib>
#include <string>
#include <vector>
#include <cstdio>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <set>
using namespace std;
#define INF 0x3f3f3f3
const int N=100005;
const int mod=1e9+7;

int a[N];

long long sum=0;

int main(){
    int t,n;
    cin>>t;
    while (t--) {
        a[0]=INF;
        sum=26;
        cin>>n;
        for (int i=1; i<=n-1; i++) {
            scanf("%d",&a[i]);
        }
        int flag=1;
        for (int i=1; i<=n-1; i++) {
            if (a[i]+i>n) {
                flag=0;
                break;
            }
            if (a[i]>=a[i-1]&&a[i]&&a[i-1]) {
                flag=0;
                break;
            }
        }
        for (int i=2; i<=n-1; i++) {
            if (a[i-1]-a[i]!=0) {
                for (int j=i; j<=i-2+a[i-1]; j++) {
                    if (a[j-1]-a[j]!=1) {
                        flag=0;
                        break;
                    }
                }
            }
        }
        int i=1;
        while (i<=n-1) {
            if (a[i]==0) {
                sum*=25;
                sum%=mod;
            }
            i++;
        }
        if (flag)   cout<<sum<<endl;
        else cout<<"0"<<endl;
    }
    return 0;
}