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) for _ in range(N)]
i = 0
P = 10 ** 9 + 7
while i * N <= S:
    dp[0][i * N] += 1
    i += 1
for i in range(1,N):
    for j in range(S+1):
        k = 0
        while j + k * (N-i) <= S:
            dp[i][j+k*(N-i)] += dp[i-1][j]
            k += 1
    for j in range(S + 1):
        dp[i][j] %= P
print(dp[-1][S])