#include <bits/stdc++.h>
#define ALL(A) (A).begin(), (A).end()
#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

int dx[] = { 0, 1, -1, 0, 1, -1, 1, -1 };  // i<4:4way i<8:8way
int dy[] = { 1, 0, 0, -1, 1, -1, -1, 1 };

const ll mod = 1e9 + 7;
const ll INF = -1 * ((1LL << 63) + 1);
const int inf = -1 * ((1 << 31) + 1);

int ans;
int n,s,k;

int a[101][20001];

int f(int n,int s){
    // k = 0  のときn人でちょうどs円払う方法
    if(a[n][s])return a[n][s];
    if(n==0)return !s;
    return a[n][s] = (f(n-1,s) + (s<n?0:f(n,s-n)))%mod;
}
int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    cin >> n >> s >> k;
    s -= k*((n-1)*n)/2;
    if(s<0){
        cout << 0 << endl;
        return 0;
    }else{
        //cout << s << endl;
        cout << f(n,s) << endl;
    }
}