void solve();

int main() {
	solve();
	return 0;
}

//////////////////////////////////////////////////
//////////////////////////////////////////////////
#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <queue>
#include <functional>
#include <map>


using namespace std;

typedef pair<int, int> pii;

//分割数求める
//和S以下、n分割、M剰余
//保存用空vector<int>指定
//もうめんどくさいから全部long intで(適当)
void divisionNumber(long int S, long int n, long int M,vector<long int>& v) {
	v.resize(S+1);
	for (int n = 0; n <= S; n++)v[n] = 0;
	v[0] = 1;
	for (int i = 1; i <= n; i++) {   //i分割
		for (int j = 0; j <= S; j++) {
			if (j - i >= 0)v[j] += v[j - i];
			if (v[j] >= M)v[j] -= M;
		}
	}
	return;
}

long int N, S, K;
long int M;

void solve() {
	cin >> N >> S >> K;
	M = 1000000000 + 7;
	vector<long int> v;
	if (S - (N - 1)*N*K / 2 < 0) {
		cout << 0 << endl;
		return;
	}
	divisionNumber(S - (N - 1)*N*K / 2, N, M, v);
	cout << v[N] << endl;
	return;
}