def solve(N, S):
    global dp
    mod = 10**9 + 7
    if S < 0:
        return 0
    if S == 0:
        return 1
    dp = [[-1] * (S + 1) for i in range(N + 1)]
    for n in range(N + 1):
        dp[n][0] = 1
    for s in range(S + 1):
        dp[1][s] = 1
    return dfs(N, S, mod)

def dfs(n, s, mod):
    global dp
    if dp[n][s] != -1:
        return dp[n][s]
    dp[n][s] = sum(dfs(n-1, ss, mod) for ss in range(s, -1, -n)) % mod
    return dp[n][s]
    

N, S, K = map(int, input().split())
S -= N * (N-1) * K // 2
print(solve(N, S))