#include <iostream>
#include <cmath>
#include <climits>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <functional>
#include <algorithm>
#include <sstream>
#include <map>
#include <set>
#include <utility>

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define DEBUG(x) cout<<#x<<": "<<x<<endl

using namespace std;

typedef pair<int,int> P;
typedef long long int LL;

const int MAX_N=100,MAX_S=20000,MAX_K=100;
const int mod=1000000007;
LL dp[MAX_N][MAX_S+1];

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int N,S,K;
	cin>>N>>S>>K;
	RREP(i,N){
		//DEBUG(i);
		REP(j,S+1){
		//	DEBUG(j);
			if(i==N-1){
				dp[i][j]=1;
			}else{
				/*if(N-i-1<=j&&j+(N-i)<=S){
					//cout<<i<<' '<<j<<endl;
					//if(!(0<=j+(N-i)-(N-i-1)*K&&j+(N-i)-(N-i-1)*K<=S))	cout<<"hoge"<<endl;
					//if(dp[i][j+(N-i)]>=0&&dp[i+1][j+(N-i)-(N-i-1)*K]>=0&&dp[i][j+(N-i)]-dp[i+1][j+(N-i)-(N-i-1)*K]<=0)	cout<<i<<' '<<j<<endl;	
					dp[i][j]=(dp[i][j+(N-i)]-dp[i+1][j+(N-i)-(N-i-1)*K])%mod;*/
				if(j-K*(N-i-1) > N-i){
					dp[i][j] = dp[i][j-(N-i)]+dp[i+1][j-K*(N-i-1)];
					dp[i][j] %= mod;
				}else{
					for(int k=0;0<=j-K*(N-i-1)-k*(N-i);k++){
						dp[i][j]+=dp[i+1][j-K*(N-i-1)-k*(N-i)];
						dp[i][j]%=mod;
					}
				}
			}
		}
	}
	/*REP(i,N){
		REP(j,S+1){
			cout<<dp[i][j]<<' ';
			/*if(dp[i][j]>=mod){
				cout<<i<<' '<<j<<endl;
			}
		}
		cout<<endl;
	}*/
	cout<<dp[0][S]<<endl;
	return 0;
}