···

def triangles():

    L = [1]

    while True:

        yield L

        L = [0] + L + [0]

        L = [L[i] + L[i+1] for i in range(len(L)-1)]

try:

    n = int(input("请输入一个正整数："))

    if n <= 0:

        raise ValueError

except ValueError:

    print("输入错误，请输入一个正整数。")

else:

    for i, t in enumerate(triangles()):

        print(' '.join([str(x).center(4) for x in t if x != 0]).center(4*n))

        if i == n - 1:

            break

···