//Δ_1004
#include<iostream>
#include<cstdio>
#include<fstream>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<bitset>
#include<cmath>
#include<cstring>
#include<cstdlib>
using namespace std;
typedef long long LL;
typedef double DB;
const int N = 1111;
const int MO = 1e9+7;
void ad(int&x,int y){
    x+=y;
    if(x>=MO)
        x-=MO;
}
int mul(int x,int y){
    return (LL)x*y%MO;
}
int n,m,k=11,f[N][N][12];
int main()
{
    int T,i,j,o;
    scanf("%d",&T);
    while(T--){
        scanf("%d%d",&n,&m);
        memset(f,0,sizeof(f));
        f[1][0][0]=1;
        for(i=1;i<n;i=i+1){
            for(j=0;j<=m;j=j+1){
                for(o=0;o<k;o=o+1){
                    if(!f[i][j][o])
                        continue;
                    ad(f[i+1][j+1][o+1],mul(f[i][j][o],i));
                    ad(f[i+1][j][0],f[i][j][o]);
                }
            }
        }
        if(!f[n][m][0])
            f[n][m][0]=-1;
        printf("%d\n",f[n][m][0]);
    }
    return 0;
}