#include<stdio.h>
#include<string.h>
#include<iostream>
#include<vector>
#include<math.h>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<string>
#include<stdlib.h>
#include<algorithm>
using namespace std;
typedef long long LL;
const int maxn = 1e6;
const LL mod = 1000000007;
int a[maxn];
int main(){
    int cas ;
    scanf("%d",&cas);
    while(cas--){
        int n, flag = 0, c = 0;
        scanf("%d",&n);
        for(int i = 1; i < n; i++){
            scanf("%d",&a[i]);
            if(!a[i]) c++;
            if(a[i] > n-i){ //限制条件
                flag = 1;
            }
            if(a[i-1] != 0 && a[i-1] - a[i] != 1){  //减1递减
                flag = 1;
            }
        }
        if(flag){
            puts("0"); continue;
        }
        LL ans = 26;
        for(int i = 1; i <= c; i++){
            ans = (ans * 25) % mod;
        }
        printf("%lld\n",ans);
    }
    return 0;
}
/*
55
5
0 1 0 4
5
0 1 0 2
4
3 2 1
5
0 1 2 0
7
0 0 3 2 1 0

*/