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

Home > Numbers
Factorial Tremors (Posted on 2019-01-16) Difficulty: 3 of 5
What decimal digit occurs most often in the sequence of factorials from 77777! to 77877! inclusive?

Note: This can be solved by logic. No computer is needed.

No Solution Yet Submitted by Danish Ahmed Khan    
No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
An observation | Comment 3 of 4 |
The numbers below 100000 are small enough that the answer is almost certainly zero.  However, the proportion of zeros at the end of n! does tend to decrease toward zero as n increases.

If I get a chance I may do a bit of statistical analysis on the likelihood a digit can surpass zero for some large n! assuming the digits in the non-trailing zeros portion.

(It can also be mentioned the first digit and digit before the trailing zeros are not zero.)

  Posted by Jer on 2019-01-16 22:45:17
Please log in:
Remember me:
Sign up! | Forgot password

Search body:
Forums (3)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (2)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Copyright © 2002 - 2020 by Animus Pactum Consulting. All rights reserved. Privacy Information