mod = 10**9 + 7

n,s,k = map(int,input().split())

#dp[i][j] : i番目までつかって, 今
dp = [[0] * (n+1) for i in range(s+1)]
dp[0][0] = 1

for i in range(1,s+1):
	for j in range(1,n+1):
		if i-j >= 0:
			dp[i][j] = (dp[i-1][j-1] + dp[i-j][j]) % mod

for i in range(s+1):
	for j in range(1,n+1):
		dp[i][j] = (dp[i][j] + dp[i][j-1]) % mod

#print(*dp,sep="\n")

j = s - n * (n-1) // 2 * k
ans = 0
while j >= 0:
	ans = (ans + dp[j][n-1]) % mod
	j -= n

print(ans)