#include<iostream>
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;
	else{for(int i=0;n>i;i++)for(int j=0;s>=j;j++)if(dp[i][j])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;}
}