#include <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cstring>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <numeric>
#include <utility>
#include <iomanip>
#include <algorithm>
#include <functional>
using namespace std;

#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
#define EACH(i, s) for (__typeof__((s).begin()) i = (s).begin(); i != (s).end(); ++i)

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P)
{ EACH(it, P) { s << "<" << it->first << "->" << it->second << "> "; } return s << endl; }

const int MOD = 1000000007;
const int MAX_N = 21000;
const int MAX_K = 110;
int PartNum[MAX_N + 1][MAX_K + 1];

void calcPartNum() {
	PartNum[0][0] = 1;
	for (int n = 0; n <= MAX_N; ++n) {
		for (int k = 1; k <= MAX_K; ++k) {
			PartNum[n][k] = PartNum[n][k - 1];
			if (n >= k) {
				PartNum[n][k] += PartNum[n - k][k];
				if (PartNum[n][k] >= MOD) PartNum[n][k] -= MOD;
			}
		}
	}
}

int N, S, K;
int main() {
	calcPartNum();
	while (cin >> N >> S >> K) {
		int n = S - N*(N - 1) / 2 * K;
		int k = N;
		if (n < 0 || n < k) cout << 0 << endl;
		else cout << PartNum[n][k] << endl;
	}
}