#pragma GCC optimize ("O3")
#pragma GCC target ("avx")
#include "bits/stdc++.h" // define macro "/D__MAI"

using namespace std;
typedef long long int ll;

#define debugv(v) printf("L%d %s => ",__LINE__,#v);for(auto e:v){cout<<e<<" ";}cout<<endl;
#define debugm(m) printf("L%d %s is..\n",__LINE__,#m);for(auto v:m){for(auto e:v){cout<<e<<" ";}cout<<endl;}
#define debuga(m,w) printf("L%d %s is => ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;
#define debugaa(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[x][y]<<" ";}cout<<endl;}
#define debugaar(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[y][x]<<" ";}cout<<endl;}
#define ALL(v) (v).begin(),(v).end()
#define repeat(l) for(auto cnt=0;cnt<(l);++cnt)
#define iterate(b,e) for(auto cnt=(b);cnt!=(e);++cnt)
#define MD 1000000007ll
#define PI 3.1415926535897932384626433832795
template<typename T1, typename T2>
ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << "(" << p.first << ":" << p.second << ")"; return o; }

#define TIME chrono::system_clock::now()
#define MILLISEC(t) (chrono::duration_cast<chrono::milliseconds>(t).count())
namespace {
    std::chrono::system_clock::time_point ttt;
    void tic() { ttt = TIME; }
    void toc() { fprintf(stderr, "TIME : %lldms\n", MILLISEC(TIME - ttt)); }
    std::chrono::system_clock::time_point tle = TIME;
#ifdef __MAI
    void safe_tle(int msec) { assert(MILLISEC(TIME - tle) < msec); }
#else
#define safe_tle(k) ;
#endif
}

#ifdef __MAI
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
#ifdef __VSCC
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#endif
namespace {
#define isvisiablechar(c) (0x21<=(c)&&(c)<=0x7E)
    class MaiScanner {
    public:
        template<typename T>
        void input_integer(T& var) {
            var = 0;
            T sign = 1;
            int cc = getchar_unlocked();
            for (; cc<'0' || '9'<cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc&&cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var*sign;
        }
        inline int c() { return getchar_unlocked(); }
        inline MaiScanner& operator>>(int& var) {
            input_integer<int>(var);
            return *this;
        }
        inline MaiScanner& operator>>(long long& var) {
            input_integer<long long>(var);
            return *this;
        }
        inline MaiScanner& operator>>(string& var) {
            int cc = getchar_unlocked();
            for (; !isvisiablechar(cc); cc = getchar_unlocked());
            for (; isvisiablechar(cc); cc = getchar_unlocked())
                var.push_back(cc);
        }
    };
}
MaiScanner scanner;




ll n, ss, kk;

ll dp[102][20002];


ll dfs(ll index, ll coin) {
    // static unordered_map<ll,ll> memo;
    if (index == n){
        return coin == 0;
    }
    
    // ll key = (index<<32) | coin;
    // if (memo.count(key)) return memo[key];
    
    if (dp[index][coin]) return dp[index][coin] - 1;
    
    ll prev = index == 0 ? -kk : 0;
    
    ll result = 0;
    for (ll vel = prev + kk; coin - vel*(n - index) >= 0; ++vel) {
        result = (result + dfs(index + 1, coin - vel*(n - index))) % MD;
    }
    //return memo[key] = result;
    dp[index][coin] = result + 1;
    return result;
}

// dfs(0,ss,-kk);


int main() {
    cin >> n >> ss >> kk;

    // fill(dp[0], dp[0] + ss + 1, 1);
    // 
    // for (int i = 1; i < n ; ++i) {
    //     for (int coin = 0; coin < ss; ++coin) {
    //         if (dp[i - 1][coin])
    //             for (int vel = kk; coin + vel*(n - i) <= ss; ++vel) {
    //                 dp[i][coin + vel*(n - i)] += dp[i - 1][coin];
    //             }
    //     }
    // }

    // cout << dp[n - 1][ss];

    cout << dfs(0, ss) << endl;

    return 0;
}