#include<iostream>
#include<iomanip>
#include<cmath>
#include<string>
#include<vector>
#include<list>
#include<algorithm>
#include<map>
#include<set>
#include<queue>
#include<stack>
using namespace std;
typedef long long ll;
#define fi first
#define se second
#define mp make_pair
#define rep(i, n) for(int i=0;i<n;++i)
#define rrep(i, n) for(int i=n;i>=0;--i)
const int inf=1e9+7;
const ll mod=1e9+7;
const ll big=1e18;
const double PI=2*asin(1);

ll DP[105][20005];

int main() {
    ll N, S, K;
    cin>>N>>S>>K;
    S -= (N-1)*N/2*K;
    if(S<0) cout<<0<<endl;
    else {
        for(int i=0;i<=S;++i){
            DP[1][i] = 1;
        }
        for(int i=1;i<=N;++i){
            DP[i][0] = 1;
        }
        for(int i=1;i<=N;++i){
            for(int j=1;j<=S;++j){
                if(j>=i){
                    DP[i][j] = DP[i][j-i] + DP[i-1][j];
                    DP[i][j] %= mod;
                }
                else DP[i][j] = DP[i-1][j];
            }
        }
        cout<<DP[N][S]<<endl;
    }
}