import sys

sys.setrecursionlimit(10 ** 6)
def MI(): return map(int, sys.stdin.readline().split())

class mint:
    def __init__(self, x):
        self.__x = x % md

    def __str__(self):
        return str(self.__x)

    def __add__(self, other):
        if isinstance(other, mint): other = other.__x
        return mint(self.__x + other)

    def __sub__(self, other):
        if isinstance(other, mint): other = other.__x
        return mint(self.__x - other)

    def __rsub__(self, other):
        return mint(other - self.__x)

    def __mul__(self, other):
        if isinstance(other, mint): other = other.__x
        return mint(self.__x * other)

    __radd__ = __add__
    __rmul__ = __mul__

    def __truediv__(self, other):
        if isinstance(other, mint): other = other.__x
        return mint(self.__x * pow(other, md - 2, md))

    def __pow__(self, power, modulo=None):
        return mint(pow(self.__x, power, md))

md=10**9+7
def main():
    # n人でx円払う方法
    memo={}
    def p(n,x):
        if n==1:return mint(1)
        if (n,x) in memo:return memo[n,x]
        res=0
        for a in range((x-k*n*(n-1)//2)//n+1):
            res+=p(n-1,x-a*n-k*(n-1))
        memo[n,x]=res
        return res

    n,s,k=MI()
    print(p(n,s))

main()