#define _CRT_SECURE_NO_WARNINGS
//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
//#define int ll
//#define endl "\n"
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
#define all(c) (c).begin(), (c).end()
#define loop(i,a,b) for(ll i=a; i<ll(b); i++)
#define rep(i,b) loop(i,0,b)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
template<class T> ostream & operator<<(ostream & os, vector<T> const &);
template<int n, class...T> typename enable_if<(n>=sizeof...(T))>::type _ot(ostream &, tuple<T...> const &){}
template<int n, class...T> typename enable_if<(n< sizeof...(T))>::type _ot(ostream & os, tuple<T...> const & t){ os << (n==0?"":" ") << get<n>(t); _ot<n+1>(os, t); }
template<class...T> ostream & operator<<(ostream & os, tuple<T...> const & t){ _ot<0>(os, t); return os; }
template<class T, class U> ostream & operator<<(ostream & os, pair<T,U> const & p){ return os << "(" << p.first << ", " << p.second << ") "; }
template<class T> ostream & operator<<(ostream & os, vector<T> const & v){ rep(i,v.size()) os << v[i] << (i+1==(int)v.size()?"":" "); return os; }
template<class T> inline bool chmax(T & x, T const & y){ return x<y ? x=y,true : false; }
template<class T> inline bool chmin(T & x, T const & y){ return x>y ? x=y,true : false; }
#ifdef DEBUG
#define dump(...) (cerr<<#__VA_ARGS__<<" = "<<mt(__VA_ARGS__)<<" ["<<__LINE__<<"]"<<endl)
#else
#define dump(...)
#endif
ll const mod = 1000000007;
// ll const inf = 1LL<<60;

int const MAX_N = 30000;
int const MAX_M = 200;
int n, m;
ll dp[MAX_M + 1][MAX_N + 1]; // DP テーブル
int solve() {
    dp[0][0] = 1;
    for (int i = 1; i <= m; i++) {
        for (int j = 0; j <= n; j++) {
            if (j - i >= 0) {
                dp[i][j] = (dp[i - 1][j] + dp[i][j - i]) % mod;
            } else {
                dp[i][j] = dp[i - 1][j];
            }
        }
    }
    return dp[m][n];
}

signed main(){
    int N,S,K;
    while(cin >> N >> S >> K){
        ::n = S-N*(N-1)/2*K;
        ::m = N;
        dump(n,m);
        cout << solve() << endl;
    }
}