#include <bits/stdc++.h>

using namespace std;
#define endl "\n"
typedef long long ll;
const int mod = 1e9 + 7;
ll a[101][20010], l[101][20010];
int n, s, k;
int f(int n, int s) {
  if (l[n][s]++) return a[n][s];
  if (n == 0) return !s;
  return a[n][s] = (f(n - 1, s) + (s < n ? 0 : f(n, s - n))) % mod;
}
void solved() {
  memset(l, 0, sizeof l);
  memset(a, 0, sizeof a);
  cin >> n >> s >> k;
  if (n * (n - 1) / 2 * k > s) {
    cout << 0 << endl;
    return;
  }
  s -= n * (n - 1) / 2 * k;
  cout << f(n, s) << endl;
}

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  /*int t = 1;
  cin >> t;
  while (t--)*/
  solved();

  return 0;
}