[seqfan] Re: phi-antipalindromic numbers

Vladimir Shevelev shevelev at bgu.ac.il
Mon Sep 6 09:35:55 CEST 2010

I am grateful to Al, Hans, Richard and Doug for the constructive part of the discussion.


----- Original Message -----
From: Douglas McNeil <mcneil at hku.hk>
Date: Monday, September 6, 2010 3:55
Subject: [seqfan] Re: phi-antipalindromic numbers
To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>

> [FWIW, I find 25983 such phi-antipalindromic numbers less than 10^6,
> and I agree with Hans' half-sequence. They have a cute pattern,
> probably related to the observations in the comments.]
> Ideally good sequence invention abilities would go with good sequence
> implementation abilities, but it doesn't always work out that way.
> ISTM though that many sequences are of the sort "all non-prime
> positive integers such that phi(2*n+1) < n", i.e. numbers 
> satisfyingsome straightforward constraint.  These don't 
> even count as
> programming, and our non-programming friends shouldn't fear 
> them: it
> honestly takes less time to write a one-line "program" than it 
> does to
> write an email about it.
> Doug
> -- 
> Department of Earth Sciences
> University of Hong Kong
> _______________________________________________
> Seqfan Mailing list - http://list.seqfan.eu/

 Shevelev Vladimir‎

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