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

Home > Numbers
Mirror, mirror (Posted on 2012-05-04) Difficulty: 3 of 5
What palindromic prime number of n digits reads the same upside down or when viewed in a mirror?

Some examples for n=2 or 3:
11, 101, 181.

How far can you go?

Rem: Only digits 0,l and 8 qualify.

No Solution Yet Submitted by Ady TZIDON    
Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
A quick note and some Links (spoilers) | Comment 1 of 4
With the exception of 11, all such primes will have odd n because palindromes with an even number of digits are divisible by 11.

Here is a list of the first 22 such numbers
https://oeis.org/A068188

This site gives a very large number (n=180055)
http://mathworld.wolfram.com/TetradicNumber.html

  Posted by Jer on 2012-05-04 11:21:40
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 (14)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information