#include <iostream>
using namespace std;

int N, S, K;

long long DP[101][20001];

int main()
{
	cin >> N >> S >> K;

	DP[0][0] = 1;
	for (int k = 0; k*N <= S; k++) {
		DP[1][k*N] = DP[0][0];
	}
	for (int i = 1; i < N; i++) {
		for (int j = 0; j <= S; j++) {
			if (DP[i][j] == 0)continue;
			for (int k = K; j + k*(N - i) <= S; k++) {
				DP[i + 1][j + k*(N - i)] += DP[i][j];
				DP[i + 1][j + k*(N - i)] %= (int)1e9 + 7;
			}
		}
	}

	cout << DP[N][S] << endl;

	return 0;
}