//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#include <x86intrin.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define all(v) v.begin(), v.end()
#define allr(v) v.rbegin(), v.rend()
#define V vector
template <typename T> bool chmin(T &a, const T &b) {if(a > b){a = b; return true;} return false;}
template <typename T> bool chmax(T &a, const T &b) {if(a < b){a = b; return true;} return false;}
V<int> dx = {-1, 1,  0, 0, -1, -1,  1, 1};
V<int> dy = { 0, 0, -1, 1, -1,  1, -1, 1};

const int mod = 1e9 + 7;
int dp[20010][110];

int main () {
    int n, s, k; cin >> n >> s >> k;
    memset(dp, 0, sizeof(dp));
    s -= (n-1) * n / 2 * k;
    if (s < 0) {
        cout << 0 << endl;
        return 0;
    }
    dp[0][0] = 1;
    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];
            else dp[i][j] = dp[i][j-1];
            dp[i][j] %= mod;
        }
    }
    cout << dp[s][n] << endl;
    return 0;
}