#include <iostream>
#include <cstdint>

int main() {
	std::uint_fast32_t map[20001] = { 1 };
	std::uint_fast32_t map_tmp[20001] = { 1 };
	int n, maney, k;
	std::cin >> n >> maney >> k;
	maney -= (n - 1)*n/2*k;

	for (int i = 0; i <= maney; i++) {
		map[i] = 1;
	}
	if (maney < 0) {
		std::cout << 0 << std::endl;
		return 0;
	}
	for (int i = 1; i < n ; i++) {
		for (int j = 0; j <= maney; j++) {
			int now_maney = j;
			std::uint_fast32_t count = 0;
			while (now_maney >= 0) {
				count += map[now_maney];
				if (count > 1000000007) {
					count -= 1000000007;
				}
				now_maney -= i + 1;
			}
			map_tmp[j] = count;
		}
		for (int j = 0; j <= maney; j++) {
			map[j] = map_tmp[j];
		}
	}
	std::cout << map[maney] << std::endl;
}