#include<bits/stdc++.h>
using namespace std;
#define int long long

#ifdef LOCAL_DEBUG
  #include "LOCAL_DEBUG.hpp"
#endif

signed main(){

  int n,s,k; cin >> n >> s >> k;
  if(s < n*(n-1)*k/2) cout << 0 << endl;
  else{
    static int dp[101][20001]; //生徒iの金額が決まった時クラス合計金額がj円になる場合の数
    dp[0][0] = dp[1][0] = 1;
    for(int i = 0; i < n; i++){
      for(int j = 0; j <= s; j++){
        for(int d = k; d <= s; d++){
          if(j + d*(n-i) > s) break;
          dp[i+1][j + d*(n-i)] += dp[i][j];
          dp[i+1][j + d*(n-i)] %= 1000000007;
        }
      }
    }
    cout << dp[n][s] << endl;
  }

  return 0;
}