#include<bits/stdc++.h>
#define LL long long
using namespace std;
const int P=1e9+7;
LL dp[2005][2005]; 
int main(){
    LL res;
    dp[1][0]=1;
    for(int i=2;i<=1000;++i){
        for(int k=0;k<=1000;++k)
            dp[i][k]=dp[i-1][k];
        for(int j=max(1,i-11);j<i-1;++j){
            for(int k=0;k<=1000;++k){
                res=dp[j][k];
                for(int p=j;p<=i-2;p++)res=p*res%P;
                (dp[i][k+(i-j-1)]+=res)%=P;
            }
        }
    }
    int T;
    cin>>T;
    int n,m;
    while(T--){
        scanf("%d%d",&n,&m);
        printf("%d\n",dp[n][m]==0?-1:dp[n][m]);
    }
    return 0;
}