#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <climits>
#include <vector>
#include <numeric>
#include <complex>
#include <map>
#include <bitset>
#include <stack>
#include <queue>
#include <set>
#include <iomanip>
#include <cmath>
#include <atcoder/all>
using namespace std;
using namespace atcoder;

//#define __int64 long long
//#define long __int64
#define REP(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
const int Vec = 4;
const int Vecy[Vec] = {0,-1,0,1};
const int Vecx[Vec] = {1,0,-1,0};
const int Modd = 1000000007;


int n,s,k;
int dp[20010][110];
int dpBox, dpBall;

void print2D(int a[][110]){
    rep(i,dpBall+1){
        rep(j,dpBox+1){
            cout << dp[i][j] << " ";
        }
        cout << endl;
    }
}

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

    dpBall = s - (n * (n+1) / 2 - n) * k;
    dpBox =  n;
    // cout << "dpBall:" << dpBall << endl;
    /*
    rep(i, dpBall+1){
        dp[i][0] = 1;
    }
    rep(i, dpBox+1){
        dp[0][i] = 1;
    }
    */
   dp[0][0] = 1;

    //print2D(dp);

    for(int balli=0; balli<=dpBall; balli++){
        for(int boxi=1; boxi<=dpBox; boxi++){
            // dp[balli][boxi] = dp[balli][boxi-1] + dp[max(0, balli-boxi)][boxi];
            // dp[balli][boxi] %= Modd;

            if(balli-boxi >= 0){
                dp[balli][boxi] = dp[balli][boxi-1] + dp[max(0, balli-boxi)][boxi];
                dp[balli][boxi] %= Modd;
            }else{
                dp[balli][boxi] = dp[balli][boxi-1];
            }
        }
    }

    //print2D(dp);

    if(dpBall < 0){
        cout << 0 << endl;
    }else{
        cout << dp[dpBall][dpBox] << endl;
    }
    
    return 0;
}