mersenneforum.org > Math Hoot discussion - "Beastly primes".
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 2011-02-12, 19:16 #1 Arkadiusz   Dec 2009 33 Posts Hoot discussion - "Beastly primes".
 2011-02-12, 19:31 #2 Arkadiusz   Dec 2009 33 Posts In my opinion, there's a 'big hole' in the definition of beastly primes. http://oeis.org/A131645
2011-02-12, 19:34   #3
science_man_88

"Forget I exist"
Jul 2009
Dumbassville

26×131 Posts

Quote:
It's doesn't seem as hot as you make it sound and to be honest I think by posting a draft link you've allowed people to spam the OEIS no ?

Also you know you can edit previous sequences no ? so there's no reason to have both of them.

Last fiddled with by science_man_88 on 2011-02-12 at 19:37

2011-02-12, 19:48   #4
science_man_88

"Forget I exist"
Jul 2009
Dumbassville

26×131 Posts
typo

though now that you bring it up there's a typo on Caldwell's page.

Quote:
 A palindromic beastly prime has 666 in the center, 0's surrounding these digits, and 1 or 7 at the end. E.g., 700666007. A non-palindromic beastly prime begins with a 666, followed by 0's, with either a 1 or 7 at the right end. E.g., 6660000000001.

 2011-02-13, 02:08 #5 CRGreathouse     Aug 2006 3×1,987 Posts Heh, looks like the OEIS is spilling out onto the Mersenne forums. (If my handle doesn't make it clear, this is Charles R Greathouse IV, the editor-in-chief who commented on that link.) I'm still unclear on one point. For the palindromic version, are the primes required to start and end with the same digit, or can those be mixed? These would lead to different sequences since, e.g., 10006660007 is prime. Assuming that they must be the same I submitted a b-file with all the terms under a thousand digits. Last fiddled with by CRGreathouse on 2011-02-13 at 02:13
 2011-02-13, 14:42 #6 Christenson     Dec 2010 Monticello 179510 Posts by the usual definition of palindrome (reads the same forward as backwards), 10006660007 is *NOT* a palindrome. (but you could argue with me that it was a quasi-palindrome, since only the initial or final digit differs from a palindrome). One other problem with these sequences...their OEIS numbers don't involve 666 as substrings!!
 2011-02-13, 17:50 #7 cmd     "(^r'°:.:)^n;e'e" Nov 2008 ;t:.:;^ 11111001112 Posts
2011-02-13, 21:41   #8
CRGreathouse

Aug 2006

174916 Posts

Quote:
 Originally Posted by Christenson by the usual definition of palindrome (reads the same forward as backwards), 10006660007 is *NOT* a palindrome.
Agreed, but that need not have any bearing on the rather-arbitrary definition in use here.

2011-02-14, 03:39   #9
EdH

"Ed Hall"
Dec 2009

3,527 Posts

Quote:
 Originally Posted by cmd /\
Neat!

 2011-02-14, 06:41 #10 CRGreathouse     Aug 2006 10111010010012 Posts

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