#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using vec = vector<ll>;
using mat = vector<vec>;
using pll = pair<ll,ll>;

#define INF (1LL << 60)
#define MOD 1000000007
#define PI 3.14159265358979323846

#define REP(i,m,n) for(ll (i)=(m),(i_len)=(n);(i)<(i_len);++(i))
#define FORR(i,v) for(auto (i):v)
#define ALL(x) (x).begin(), (x).end()
#define PR(x) cout << (x) << endl
#define PS(x) cout << (x) << " "
#define SZ(x) ((ll)(x).size())
#define MAX(a,b) (((a)>(b))?(a):(b))
#define MIN(a,b) (((a)<(b))?(a):(b))
#define REV(x) reverse(ALL((x)))
#define ASC(x) sort(ALL((x)))
#define DESC(x) ASC((x)); REV((x))
#define pb push_back
#define eb emplace_back



int main()
{
    ll N, S, K;
    cin >> N >> S >> K;

    ll M = S - N * (N-1) * K / 2;
    ll ans;
    if(M < 0) ans = 0;
    else {
        mat dp(N+1, vec(M+1, 0));
        REP(i,0,N+1) dp[i][0] = 1;
        REP(i,1,N+1) {
            REP(j,1,M+1) {
                REP(k,0,j/(N-i+1)+1) {
                    dp[i][j] = (dp[i][j] + dp[i-1][j-(N-i+1)*k]) % MOD;
                }
            }
        }
        ans = dp[N][M];
    }
    PR(ans);

    return 0;
}

/*



*/