#define REP(i,n) for(int i=0; i<(int)(n); i++)

typedef long long ll;

#include <queue>
#include <cstdio>
inline int getInt(){ int s; scanf("%d", &s); return s; }

#include <set>

using namespace std;

int main(){
  const int n = getInt();
  const int s = getInt();
  const int k = getInt();
  const ll mod = 1000000007;
  vector<ll> dp(s + 1);
  dp[s] = 1;

  REP(i,n){
    const int rest = n - i;
    vector<ll> tmp(s + 1);

    for(int t = 0; t < rest; t++){
      int d = (i == 0 ? 0 : k * rest);
      int p = s - t - d;
      ll sum = 0;
      while(p >= 0){
        sum = (sum + dp[p + d]) % mod;
        tmp[p] = (tmp[p] + sum) % mod;
        p -= rest;
      }
      //REP(i,s+1) printf("%d ", (int)tmp[i]); puts("");
    }
    //puts("");

    /*
    for(int p = 0; p <= s; p++){
      for(int j = (i == 0 ? 0 : k * rest); j <= p; j += rest){
        const int q = p - j;
        tmp[q] = (tmp[q] + dp[q + j]) % mod;
      }
    }
    */
    dp.swap(tmp);
  }

  printf("%d\n", (int)dp[0]);
  return 0;
}