#include <iostream>
#include <ctime>
using namespace std;
const int mod = 1000000007;
int dp[101][20001];
main(){
	int n,s,k;cin>>n>>s>>k;
	s -= ((n+(n-1))/2)*((n+(n-1))/2+1)/2*k;
	dp[0][0] = 1;
	if(0>s){
		cout << 0 << endl;
		return 0;
	}
	for(int i = 0; n > i; i++){
		for(int j = 0; s >= j; j++){
			if(dp[i][j] != 0){
				for(int l = 0; s >= j+l*(n-i); l++)dp[i+1][j+l*(n-i)]=(dp[i+1][j+l*(n-i)]+dp[i][j])%mod;
			}
		}
	}
	cout << dp[n][s] << endl;
}