#include <bits/stdc++.h>
using namespace std;
 
#define fi first
#define se second
#define pb push_back
using vi = vector <int>;
using ll = long long;
using pii = pair <int, int>;
//~ const ll mod = 998244353;
const ll mod = 1e9 + 7;
ll qpow(ll a, ll b, ll m = mod) { ll r = 1, t = a;
	for(; b; b /= 2) { if(b & 1) r = r * t % m; t = t * t % m; } return r; }

const int N = 211, S = 2e4 + 11;

ll f[N][S];
void upd(ll &a, ll b) {
	a += b;
	a %= mod;
}

int main() {
	ios :: sync_with_stdio(false);
	
	int n, s, k; cin >> n >> s >> k;
	for(int i = 1; i < n; i ++)
		s -= i * k;
	if(s < 0) cout << 0 << '\n';
	else {
		f[0][0] = 1;
		for(int i = 1; i <= n; i ++)
			for(int j = 0; j <= s; j ++) {
				upd(f[i][j], f[i - 1][j]);
				if(j >= i) upd(f[i][j], f[i][j - i]);
			}
		cout << f[n][s] << '\n';
	}
}