#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <cstdio>
#include <queue>
#include <stack>

using namespace std;
const long INF = 1000000007;

template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val){
    std::fill( (T*)array, (T*)(array+N), val );
}

int dp[20030][200];
int main(){
  int N,S,K;
  cin >> N >> S >> K;

  dp[0][0] = 1;
  if(S<K*N*(N-1)/2){
    cout << 0 << endl;
  }else{
    S = S-K*N*(N-1)/2;
    for(int i=0;i<=S;++i){
      for(int j=1;j<=N;++j){
        if(i-j>=0){
          dp[i][j] = (dp[i][j-1]+dp[i-j][j]) % INF;
        }else{
          dp[i][j] = dp[i][j-1] % INF;
        }
      }
    }
    cout << dp[S][N]  << endl;
  }
}