#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 105
#define MAX_S 20005

ll dp[MAX_N][MAX_S];

int main() {
    int n, s, k;
    cin >> n >> s >> k;
    s -= (n - 1) * n / 2 * k;

    if(s < 0){
        cout << '0' << endl;
        return 0;
    }

    if(n == 1){
        cout << '1' << endl;
        return 0;
    }

    ll ans = 0;
    ll MOD = 1e9+7;

    drep(i,n){
        if(i == n - 1){
            rep(j,s+1){
                dp[i][j] = 1;
            }
            continue;
        }
        rep(j,s+1){
            rep(l, s+1){
                if(j - l*(n-i) < 0)break;
                dp[i][j] += dp[i+1][j-l*(n-i)];
                dp[i][j] %= MOD;
            }
        }
    }

    /*
    rep(j,s+1){
        rep(i,n){
            cout << dp[i][j] << ' ';
        }
        cout << endl;
    }
    */

    

    ans += dp[0][s];
    ans %= MOD;
    cout << ans << endl;
    return 0;
}