#include <iostream> // cin, cout, cerr, clog
#include <algorithm> // minmax, sort, swap
#include <numeric> // iota, accumulate, inner_product
#include <cstdio> // printf, scanf
#include <climits> // INT_MIN, LLONG_MIN
#include <cmath> // long, trig, pow
#include <string> // string, stoi, to_string
#include <vector> // vector
#include <queue> // queue, priority_queue
#include <deque> // deque
#include <stack> // stack
#include <map> // key-value pairs sorted by keys
#include <set> // set
#include <unordered_map> // hashed by keys
#include <unordered_set> // hashed by keys
#include <iomanip> // cout<<setprecision(n)
#include <functional> // std::function<void(int)>

#define rep(i,n) for(int i = 0; i < (n); i++)
#define ENDL '\n'
#define print(i) std::cout << (i) << '\n'

#define int long long // at least int64 > 9*10^18
#define all(v) (v).begin(), (v).end()

#define dump2(v) for(auto i:v) { for(auto j:i) std::cout << j << ' '; std::cout << "\n"; }

constexpr int MOD = 1e9+7;
struct mint
{
	int v;
	mint():v(0){}
	mint(int v):v((v+MOD)%MOD){}
	mint operator-()const{ return mint(0) - *this;}
	mint& operator+=(const mint& a){ if((v+=a.v)>=MOD) v-=MOD; return *this;}
	mint& operator-=(const mint& a){ if((v+=MOD-a.v)>=MOD) v-=MOD; return *this;}
	mint& operator*=(const mint& a){ (v*=a.v)%=MOD; return *this;}
	mint& operator/=(const mint& a){ (*this) *= a.inv(); return *this;}
	mint operator+(const mint& a)const{ return mint(*this) += a;}
	mint operator-(const mint& a)const{ return mint(*this) -= a;}
	mint operator*(const mint& a)const{ return mint(*this) *= a;}
	mint operator/(const mint& a)const{ return mint(*this) /= a;}
	bool operator<(const mint& a)const{ return v < a.v;}
	bool operator==(const mint& a)const{ return v == a.v;}
	mint pow(int k)const{mint r(1),t(v);while(k){if(k&1)r*=t;t*=t;k>>=1;} return r;}
	mint inv()const{return pow(MOD-2);}
};
std::istream& operator>>(std::istream&i,mint&a){int t;i>>t;a=mint(t);return i;}
std::ostream& operator<<(std::ostream&o,const mint&a){o<<a.v;return o;}

signed main() {
    std::ios_base::sync_with_stdio(0); 
    std::cin.tie(0);

	int n,s,k;
	std::cin >> n >> s >> k;

	s -= k*(n-1)*n/2;
	if(s<0) {
		print(0);
		return 0;
	}

	std::vector<std::vector<mint> > dp(n+1,std::vector<mint>(s+1,0));
	dp[0][0] = 1;
	rep(i,n) {
		rep(j,s+1) {
			int c = 0;
			while(j+(n-i)*c<=s) {
				dp[i+1][j+(n-i)*c] += dp[i][j];
				c++;
			}
		}
	}
	print(dp[n][s]);
	return 0;
}