#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <complex>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <iomanip>
#include <assert.h>
#include <array>
#include <cstdio>

using namespace std;

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

int const MOD = 1e9+7;

typedef long long ll;

int dp[2][20001];

int main() {

  int N, S, K; cin >> N >> S >> K;
  S -= N*(N-1)/2*K;
  if(S < 0) { cout << 0 << endl; return 0; }
  dp[0][S] = 1;
  for(int i=0; i<N; i++) {
    rep(j, 20001) dp[(i+1)&1][j] = 0;
    rep(j, S+1) {
      int* cur = &dp[i&1][j];
      if(!*cur) { continue; }
      rep(k, j/(N-i)+1) {
        int* tar = &dp[(i+1)&1][j-k*(N-i)];
        *tar += *cur;
        if(*tar >= MOD) {
          *tar -= MOD;
        }
      }
    }
  }

  cout << dp[N&1][0] << endl;

  return 0;
}