import sys
sys.setrecursionlimit(10 ** 6)


def main():
    def dfs(n, s):
        # global N, MOD
        rst = 0
        tmp = s
        if n == N - 1:
            rst += s // 2 + 1
        elif dp[n][s] >= 0:
            return dp[n][s]
        else:
            while s >= 0:
                rst += dfs(n + 1, s)
                rst %= MOD
                s -= (N - (n - 1))
        dp[n][tmp] = rst
        return rst

    N, S, K = map(int, input().split())

    MOD = 10 ** 9 + 7
    init = (N * (N - 1) * K) // 2
    if S < init:
        print(0)
    else:
        S -= init
        dp = [[-1] * (S + 1) for _ in range(N + 1)]
        rst = dfs(1, S)
        print(rst)


main()