#include <iostream>
#include <cstring>
#include <utility>
#include <vector>
#include <cstdio>
#include <queue>
#include <algorithm>
#include <map>
#include <cmath>
#include <complex>
#include <array>
#include <ctime>
#include <cassert>
#include <set>
#include <iomanip>
#include <random>
#include <cstdlib>
#include <chrono>
#include <bitset>

using namespace std;
const int mod = 1000000007;
int dp[2][1050][14];

void add(int& a, int b) {
    a += b;
    if (a >= mod) a -= mod;
}

int mul(int a, int b) {
    return 1LL * a * b % mod;
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t; cin >> t;
    while (t--) {
        int n, m;
        cin >> n >> m;
        if (n <= 2 && m == 0) {
            cout << 1 << "\n";
            continue;
        }
        if (m > n - 2) {
            cout << -1 << "\n";
            continue;
        }

        memset(dp, 0, sizeof dp);
        dp[0][0][0] = 1;
        for (int i = 2; i <= n - 1; i++) {
            int ci = i & 1;
            int ni = 1 - ci;
            for (int j = 0; j <= m; j++) {
                if (j < m) {
                    for (int k = 0; k <= 10; k++) {
                        if (k < 10) {
                            add(dp[ni][j + 1][k + 1], mul(dp[ci][j][k], i - 1));
                        }
                        add(dp[ni][j][0], dp[ci][j][k]);
                    }
                } else {
                    for (int k = 0; k <= 10; k++) {
                        add(dp[ni][j][0], dp[ci][j][k]);
                    }
                }
            }
            memset(dp[ci], 0, sizeof dp[ci]);
        }
        int ans = 0;
        int i = n & 1;
        for (int j = 0; j <= 10; j++) {
            add(ans, dp[i][m][j]);
        }
        cout << ans << "\n";
    }

}