#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double db;
typedef pair<int,int> pii;
#define fir first
#define sec second
#define rep(i,a,b) for (int i = (a) ; i <= (b) ; ++ i)
#define rrp(i,a,b) for (int i = (a) ; i >= (b) ; -- i)
#define gc() getchar()
template <typename tp>
inline void read(tp& x) {
  x = 0; char tmp; bool key = 0;
  for (tmp = gc() ; !isdigit(tmp) ; tmp = gc())
    key = (tmp == '-');
  for ( ; isdigit(tmp) ; tmp = gc())
    x = (x << 3) + (x << 1) + (tmp ^ '0');
  if (key) x = -x;
}
template <typename tp>
inline void ckmn(tp& x,tp y) {
  x = x < y ? x : y;
}
template <typename tp>
inline void ckmx(tp& x,tp y) {
  x = x < y ? y : x;
}

const int MOD = (int)(1e9 + 7);
inline void Add(int& x,int y) {
  x = x + y >= MOD ? x + y - MOD : x + y;
}
inline void Sub(int& x,int y) {
  x = x - y < 0 ? x - y + MOD : x - y;
}

const int N = 1010;
int dp[2][N][15], isok[2][N][15];
int n, m;
void solve() {
  read(n), read(m);
  memset(dp, 0, sizeof dp);
  memset(isok, 0, sizeof isok);
  dp[0][0][0] = 1;
  isok[0][0][0] = 1;
  int p = 0;
  rep (i, 2, n) {
    p ^= 1;
    memset(dp[p], 0, sizeof dp[p]);
    memset(isok[p], 0, sizeof isok[p]);
    rep (j, 0, i-1) {
      rep (k, 0, 10) {
    Add(dp[p][j][0], dp[p^1][j][k]);
    isok[p][j][0] |= isok[p^1][j][k];
    if (k < 10) {
      Add(dp[p][j+1][k+1], 1ll * (i-1) * dp[p^1][j][k] % MOD);
      isok[p][j+1][k+1] |= isok[p^1][j][k];
    }
      }
    }
  }  
  if (!isok[p][m][0]) puts("-1");
  else printf("%d\n", dp[p][m][0]);
}
int main() {
  int T;
  read(T);
  while (T --)
    solve();
  return 0;
}