#include <iostream>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <string>
#include <bitset>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <algorithm>
#include <sstream>
#include <stack>
#include <iomanip>
#include <assert.h>
using namespace std;
#define pb push_back
#define mp make_pair
typedef pair<int,int> pii;
typedef long long ll;
typedef double ld;
typedef vector<int> vi;
#define fi first
#define se second
#define fe first
#define FO(x) {freopen(#x".in","r",stdin);freopen(#x".out","w",stdout);}
#define Edg int M=0,fst[SZ],vb[SZ],nxt[SZ];void ad_de(int a,int b){++M;nxt[M]=fst[a];fst[a]=M;vb[M]=b;}void adde(int a,int b){ad_de(a,b);ad_de(b,a);}
#define Edgc int M=0,fst[SZ],vb[SZ],nxt[SZ],vc[SZ];void ad_de(int a,int b,int c){++M;nxt[M]=fst[a];fst[a]=M;vb[M]=b;vc[M]=c;}void adde(int a,int b,int c){ad_de(a,b,c);ad_de(b,a,c);}
#define es(x,e) (int e=fst[x];e;e=nxt[e])
#define esb(x,e,b) (int e=fst[x],b=vb[e];e;e=nxt[e],b=vb[e])
const int MOD=1e9+7;
#define SZ 666666
ll f[1005][1005][12];
int main()
{
    f[1][0][0]=1;
    for(int i=1;i<=1000;++i)
    {
        for(int j=0;j<=i;++j)
            for(int k=0;k<11;++k) if(f[i][j][k])
            {
                (f[i+1][j+1][k+1]+=f[i][j][k]*(ll)i)%=MOD;
                (f[i+1][j][0]+=f[i][j][k])%=MOD;
            }
    }
    int T,n,m;
    cin>>T;
    while(T--)
    {
        cin>>n>>m;
        ll ans=f[n][m][0];
        ans=(ans%MOD+MOD)%MOD;
        if(!ans) ans=-1;
        cout<<ans<<"\n";
    }
}