#pragma GCC optimize(1)
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping")
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-fwhole-program")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-fstrict-overflow")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-skip-blocks")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("-funsafe-loop-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
#include<bits/stdc++.h>
#define LL long long
#define rint register int
using namespace std;bool h1;
int f[2][1005][12],P=1e9+7;
int n,m,t,T;
inline int rd(){
    int _s=0;char ch=getchar();
    while(ch<48||ch>57)ch=getchar();
    while(ch>=48&&ch<=57)_s=(_s<<1)+(_s<<3)+ch-48,ch=getchar();
    return _s;
}
bool h2;int main(){
    T=rd();
//    for(int i=1;i<=100;i++)cout<<i<<' '<<((i-2)/11+2)<<endl;
    while(T--){
        n=rd(),m=rd();
        if(n==1){
            if(m>0)puts("-1");
            else puts("1");
            continue;
        }
        if(m>n-2){puts("-1");continue;}
        if(n-((n-2)/11+2)<m){puts("-1");continue;}
        memset(f,0,sizeof(f));
        f[t][0][0]=1;
        for(rint i=2;i<=n;i++){
            for(rint j=0;j<=m;j++)
                for(rint k=0;k<=10;k++){
                    (f[!t][j][0]+=f[t][j][k])%=P;
                    if(j<m&&k<10)(f[!t][j+1][k+1]+=1ll*f[t][j][k]*(1ll*i-1ll)%P)%=P;
                    f[t][j][k]=0;
                }
            t^=1;
        }
        printf("%d\n",!f[t][m][0]?-1:f[t][m][0]);
    }
    return 0;
}