#include<bits/stdc++.h>
#define N 1005
using namespace std;
const int P=1e9+7;
int fac[N],inv[N],f[N][N][11];
int C(int x, int y){
    if (x<y) return 0;
    return 1ll*fac[x]*inv[y]%P*inv[x-y]%P;
}
int main(){
    int T; scanf("%d",&T);
    //fac[0]=1;for (int i=1;i<=n;i++) fac[i]=1ll*fac[i-1]*i%P;
    //inv[0]=inv[1]=1;for (int i=2;i<=n;i++) inv[i]=1ll*(P-P/i)*inv[P%i]%P;
    while (T--){
        int n,m; scanf("%d%d",&n,&m);
        for (int i=0;i<=n;i++)
            for (int j=0;j<=m;j++)
                for (int k=0;k<=10;k++) f[i][j][k]=0;
        f[1][0][0]=1;
        for (int i=1;i<n;i++)
            for (int j=0;j<=m;j++)
                for (int k=0;k<=10;k++)
                    if (f[i][j][k]){
                        if (k<10) f[i+1][j+1][k+1]=(f[i+1][j+1][k+1]+1ll*f[i][j][k]*i)%P;
                        f[i+1][j][0]=(f[i+1][j][0]+f[i][j][k])%P;
                    }
        printf("%d\n",f[n][m][0]==0?-1:f[n][m][0]);
    }
}