#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using Edge = pair<int, int>;
using Graph = vector<vector<Edge>>;
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define SORT(v) sort((v).begin(), (v).end())
#define RSORT(v) sort((v).rbegin(), (v).rend())
const ll MOD = 1000000007;
const ll nmax = 8;
const ll INF = 1e9;
bool graph[nmax][nmax];
vector<vector<ll>> dist = vector<vector<ll>>(nmax, vector<ll>(nmax, INF));
void warshall_floyd(ll n)
{
    for (size_t i = 0; i < n; i++)
    {
        for (size_t j = 0; j < n; j++)
        {
            for (size_t k = 0; k < n; k++)
            {
                dist[j][k] = min(dist[j][k], dist[j][i] + dist[i][k]);
            }
        }
    }
}

class UnionFind
{
public:
    vector<ll> Parent;

    UnionFind(ll N)
    {
        Parent = vector<ll>(N, -1);
    }
    ll find(ll A)
    {
        if (Parent[A] < 0)
            return A;
        return Parent[A] = find(Parent[A]);
    }

    ll size(ll A)
    {
        return -Parent[find(A)];
    }

    bool Union(ll A, ll B)
    {
        A = find(A);
        B = find(B);
        if (A == B)
        {
            return false;
        }
        if (size(A) < size(B))
            swap(A, B);

        Parent[A] += Parent[B];
        Parent[B] = A;

        return true;
    }
};

ll gcd(ll a, ll b)
{
    if (b == 0)
        return a;
    return gcd(b, a % b);
}

ll lcm(ll a, ll b)
{
    ll g = gcd(a, b);
    return a / g * b;
}

ll mulMod(ll a, ll b)
{
    return (((a % MOD) * (b % MOD)) % MOD);
}

ll powMod(ll a, ll p)
{
    if (p == 0)
    {
        return 1;
    }
    else if (p % 2 == 0)
    {
        ll half = powMod(a, p / 2);
        return mulMod(half, half);
    }
    else
    {
        return mulMod(powMod(a, p - 1), a);
    }
}

ll ceil(ll a, ll b)
{
    return (a + b - 1) / b;
}

bool isOK(map<char, ll> cnter, ll cnt, ll K, char c)
{
    if (cnt == K)
    {
        if (cnter[c] >= 1)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    else if (cnt == K - 1)
    {
        if (cnter[c] == 0)
        {
            return true;
        }
    }
    return false;
}
ll dp[110][20010];
int main()
{
    ll N, S, K;
    cin >> N >> S >> K;
    ll must = ((N - 1) * N / 2) * K;
    S -= must;

    dp[0][0] = 1;
    if (S < 0)
    {
        cout << 0 << endl;
        return 0;
    }
    for (int i = 1; i <= N; i++)
    {
        for (int j = 0; j <= S; j++)
        {
            if (j - i >= 0)
            {
                dp[i][j] = (dp[i - 1][j] + dp[i][j - i]) % MOD;
            }
            else
            {
                dp[i][j] = dp[i - 1][j];
            }
        }
    }
    cout << dp[N][S] << endl;

    return 0;
}