All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Just Math
Curious Consecutive Cyphers II (Posted on 2009-02-23) Difficulty: 2 of 5
A positive integer T is defined as a factorial tail if there exists a positive integer P such that the decimal expansion of P! ends with precisely T consecutive zeroes, and (T+1)th digit from the right in P! is nonzero.

How many positive integers less than 1992 are not factorial tails?

No Solution Yet Submitted by K Sengupta    
No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
re(3): Computer Solution | Comment 5 of 7 |
(In reply to re(2): Computer Solution by Charlie)

after seeing your posts I reevaluated my computations and I agree with your soultions.  I got my solution by making an erroneous assumption about the differences between each consecutive non-factorial tail number.  While most of the differences are in fact 6 as I orignally assumed there is a differnence of 1 every 6'th difference and that caused the error in my computation of the total number.
  Posted by Daniel on 2009-02-23 13:10:46

Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (4)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information