#include <bits/stdc++.h>
#define debug(x) cerr << #x << ": " << x << '\n';
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int INF = (int)1e9;
int MOD = 1000000007;

int N, S, K;
ll dp[101][20001];

int main(void){
    cin >> N >> S >> K;
    int money = S - N*(N-1)*K/2;
    int res;
    if(money < 0){
        res = 0;
    }else{
        dp[0][0] = 1;
        for(int i = 1; i <= N; i++){
            for(int j = 0; j <= money; j++){
                dp[i][j] = dp[i-1][j] % MOD;
                if(j-i >= 0) dp[i][j] = ((dp[i][j-i] + dp[i-1][j]) % MOD);

            }
        }

        res = dp[N][money];
    }

    cout << res << '\n';

    return 0;
}