#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import operator
from itertools import starmap, tee
from functools import lru_cache


def pairwise(iterable):
    """
    s -> (s0,s1), (s1,s2), (s2,s3), ...
    https://docs.python.org/3/library/itertools.html#itertools-recipes
    """
    a, b = tee(iterable)
    next(b, None)
    return zip(a, b)


def pascal_row(n):
    """
    Print the nth row of a Pascal triangle
    """
    if n < 2:
        return (x for x in [1])
    else:
        def dispatch():
            yield 1
            yield from starmap(operator.add, pairwise(pascal_row(n-1)))
            yield 1
        return dispatch()


def pascal(n):
    """
    Print an n-order Pascal triangle
    """
    for i in range(1, n):
        print(pascal_row(i))

print([x for x in pascal_row(500)])