#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const ll mod = 1e9 + 7;
ll dp[2][1010][11];

int main() {
    int T; cin >> T;
    while (T--) {
        int n, m; cin >> n >> m;
        n -= 2;
        if (n <= 0 && m == 0) cout << 1 << endl;
        else if (m + ((m - 1) / 10) > n) cout << -1 << endl;
        else {
            memset(dp[1], 0, sizeof dp[1]);
            dp[1][0][0] = 1, dp[1][1][1] = 1;
            for (int i = 2; i <= n; i++) {
                memset(dp[i % 2], 0, sizeof dp[i % 2]);
                dp[i % 2][0][0] = dp[(i - 1) % 2][0][0];
                for (int j = 1; j <= m; j++) {
                    dp[i % 2][j][0] = dp[(i - 1) % 2][j][0];
                    for (int k = 1; k < 11; k++) {
                        dp[i % 2][j][k] = dp[(i - 1) % 2][j - 1][k - 1] * i % mod;
                        dp[i % 2][j][0] = (dp[i % 2][j][0] + dp[(i - 1) % 2][j][k]) % mod;
                    }
                }
            }
            ll ans = 0;
            for (int i = 0; i < 11; i++)
                ans = (ans + dp[n % 2][m][i]) % mod;
            cout << ans << endl;
        }
    }
    return 0;
}