User blog comment:Deedlit11/Bignum Bakeoff appetizer/@comment-10281778-20141123040319/@comment-5529393-20150303234326

Whoops, I missed this reply for a long while now. I'm not familiar with the lambda function in Python, but it seems to work for the test values I gave it, so good job!

It looks the function still works with y/b instead of y//b:

i = 9 ** 9 ** 9 b = 2

B = lambda y,x=0:y and y % b * (b*b)**B(x) + B(y/b,x+1)

while i:   i = B(i)-1 b *= b print(b)

83 characters according to gedit.