#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second

const ll MOD = 1000000007;
const ll MOD2 = 998244353;
const ll INF = 1LL << 60;
const ll N_MAX = 2e5;

int main(){
    ll n, s, k;
    cin >> n >> s >> k;

    s-=(n-1)*n*k/2;
    if(s < 0){
        cout << 0 << endl;
        return 0;
    }

    vector<vector<ll>> dp(n+1, vector<ll>(s+1, 0));
    dp[0][0] = 1;
    for(ll i=1; i<=n; i++){
        for(ll j=0; j<=s; j++){
            for(ll k=j; k>=0; k-=i){
                dp[i][j] += dp[i-1][k];
                dp[i][j] %= MOD;
            }
        }
    }
    cout << dp[n][s] << endl;
}