#include <stdio.h>
#include <string.h>
#include <algorithm>
#define MN 1000
typedef long long LL;
const int mod=1000000007;

int n,m,f[MN][MN][11]; //f[长度][数量][连续数量]

int calc(int n){
    return std::max((n-2)-(n-2)/11,0);
}

void solve(){
    scanf("%d%d",&n,&m);
    memset(f,0,sizeof(f));
    if(m>calc(n)){
        puts("-1");
        return;
    }
    f[1][0][0] = 1;
    for(int i=2;i<=n-1;i++){
        int lim=std::min(i,m);
        for(int j=0;j<=lim;j++){
            int lim=std::min(j,10);
            for(int k=0;k<=lim;k++)
                f[i][j][0] = (f[i][j][0]+f[i-1][j][k])%mod;
            for(int k=1;k<=lim;k++)
                f[i][j][k] = (1ll*f[i-1][j-1][k-1]*(i-1))%mod;
        }
    }
    int ans = 0;
    for(int k=0;k<=10;k++)
        ans = (ans+f[std::max(n-1,1)][m][k])%mod;
    printf("%d\n",ans);
}

int main(){
    int T; scanf("%d",&T);
    while(T--) solve();
}