#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 dp[101][20002];

int f(int n,int s){
    // K = 0 のとき n人でsを分ける方法 
    if(n == 0 && s == 0)return 1;
    if(n<=0 || s<0)return 0;
    if(dp[n][s]!=-1)return dp[n][s];

    dp[n][s] = f(n-1,s) % mod + f(n,s-n) % mod;
    return dp[n][s] % mod;
}

int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    rep(i,101)rep(j,20002)dp[i][j] = -1;
    int N,S,K;
    cin >> N >> S >> K;
    S -= K*N*(N-1)/2;
    cout << f(N,S) % mod << endl;
}