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

typedef unsigned long long ll;
const ll p = 1e9 + 7;

ll dp[1010][1010][12];
int main() {
    int t;
    scanf("%d", &t);
    while(t--) {
        int n, m;
        scanf("%d%d", &n, &m);
        dp[0][0][0] = 1;
        for(int i = 1; i <= n - 1; i++) {
            for(int j = 0; j <= min(i, m); j++) {
                for(int k = 0; k <= min(10, j); k++) {
                    dp[i][j][k] = 0;
                    dp[i][j][0] = (dp[i][j][0] + dp[i - 1][j][k]) % p;
                    if(k && dp[i - 1][j - 1][k - 1]) dp[i][j][k] = (dp[i][j][k] + (i - 1) * dp[i - 1][j - 1][k - 1]) % p;
                }
            }
        }
        ll ans = 0;
        for(int i = 0; i <= 10; i++) ans = (ans + dp[n - 1][m][i]) % p;
        if(ans == 0) printf("-1\n");
        else cout << ans << endl;
    }
    return 0;
}