sinh

    >>> def fak(n):
    ...     if n <= 1:
    ...         return 1
    ...     return n * fak(n-1)

    >>>def binom(n,k): 
    ... return fak(n) / (fak(k) * fak(n-k))
    
    >>> n=137
    >>> k=37
    >>> binom(n,k)
    3902541575254646835963436276286280L