# import sys
# sys.setrecursionlimit(10 ** 6)


# def dfs(n, s):
#     global N, S, K
#     rst = 0
#     if n == N - 1:
#         rst += s // 2 + 1

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 = [[0] * (N + 1) for _ in range(S + 1)]
    dp[0][0] = 1
    for i in range(S + 1):
        for j in range(N + 1):
            if i - j >= 0:
                dp[i][j] = (dp[i][j - 1] + dp[i - j][j]) % MOD
            else:
                dp[i][j] = (dp[i][j - 1]) % MOD
    print(dp[S][N])