#include <bits/stdc++.h>

#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define fore(i,a) for(auto &i:a)
#define all(x) (x).begin(),(x).end()
typedef long long ll; const int inf = INT_MAX / 2; const ll infl = 1LL << 60;
template<class T>bool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; }
#define pint pair<int,int>
#define pll pair<ll,ll>
const ll modl=1000000007;

using namespace std;
vector<vector<ll>> dp;

int main(void)
{   
	ll N=0,S=0,K=0;
	cin >> N >> S >> K;
	
	//1人目が0円の時、全体で
	// S-=K*(N*(N-1)/2);
	
	// if(S<=0){
	// 	cout << 0 << endl;
	// 	return 0;
	// }
	
	dp.assign(N+1,vector<ll>(S+1,0));
	
	ll num=0;
	// rep(i,0,S+1)	{
	while(1){
		if((N)*(num)<=S){
			dp[0][(N)*(num)]=1;
			num++;
		}		
		else{
			break;
		}		
	}
	
  	// dp[0][0]=1;
	rep(i,0,N-1){
		rep(j,0,S+1){
			num=0;
			if(dp[i][j]!=0){
				while(1){
					if(j+(N-(i+1))*(K+num)<=S){
						dp[i+1][j+(N-(i+1))*(K+num)]+=dp[i][j]%modl;
						dp[i+1][j+(N-(i+1))*(K+num)]%=modl;
						num++;
					}		
					else{
						break;
					}		
				}
			}
			// if(j!=0){
			// 	dp[i+1][j]+=dp[i+1][j-1]%modl;
			// 	dp[i+1][j]%=modl;
			// }
		}
	}
	if(dp[N-1][S]<0)cout << dp[N-1][S]+modl << endl;
	else cout << dp[N-1][S] << endl;
	// cout << endl;
	// rep(i,0,N+1){
	// 	cout << i << ": " ;
	// 	rep(j,0,S+1){
	// 		cout << dp[i][j] << " ";
	// 	}
	// 	cout << endl;
	// }
    return 0;
}