#include <iostream>
using namespace std;
#define ll long long int
int n, s, k;
ll dp[101][20001], mod = 1e9+7;
ll dfs(int i, int s){
    if(s < 0) return 0;
    if(i == n-1) return 1;
    if(dp[i][s] != -1) return dp[i][s];
    dp[i][s] = dfs(i, s-n+i);
    dp[i][s] += dfs(i+1, s);
    dp[i][s] %= mod;
    return dp[i][s];
}
int main(){
    cin >> n >> s >> k;
    for(int i=0; i<n; ++i)
        for(int j=0; j<=s; ++j)
            dp[i][j] = -1;
    s -= (n-1)*n/2*k;
    cout << dfs(0, s) << endl;
    return 0;
}