#include<cstdio>
#include<bits/stdc++.h>
typedef long long int ll;
#define REP(i, n) for(int i = 0; i < (n); i++)
#define FOR_IN(i, a, b) for(int i = (a); i < (b); i++)
#define BETWEEN(x, a, b) ((x) >= (a) && (x) <= (b))
#define LOG(...) fprintf(stderr, __VA_ARGS__)

using namespace std;

/*
n s k

n 100
s 20000
k 100
 */

ll pow(int x, int n){
  return n == 0 ? 1 : x * pow(x, n - 1);
}

const int MAX = pow(10,9) + 7;

int n,s,k,S;
int dp[101][20001];

int main(){
  cin >> n >> s >> k;
  S = s - n * (n - 1) * k / 2;

  REP(j,S+1)
    dp[1][j] = 1;
  
  FOR_IN(i,2,n+1){
    REP(j,S+1){
      if(j>=i)
        dp[i][j] = (dp[i][j-i] + dp[i-1][j]) % MAX;
      else
        dp[i][j] = dp[i-1][j];
    }
  }

  cout << dp[n][S] << endl;
  return 0;
}