N,S,K = map(int,input().split())
D = K * (N-1) * N // 2
import sys
if S < D:
    print(0)
    exit()
S -= D
dp = [0] * (S+1)
i = 0
P = 10 ** 9 + 7
while i * N <= S:
    dp[i * N] += 1
    i += 1
for i in range(1,N-1):
    nx = [0] * (S+1)
    for j in range(S+1):
        k = j
        while k <= S:
            nx[k] += dp[j]
            nx[k] %= P
            k += N - i
    dp = nx
ans = 0
for j in range(S+1):
    ans = (ans + dp[j]) % P
print(ans)