[seqfan] Re: Aperiodic palindromes
arndt at jjj.de
Thu Nov 25 10:45:51 CET 2010
* Charles Greathouse <charles.greathouse at case.edu> [Nov 25. 2010 09:00]:
> There are several sequences in the OEIS dealing with "aperiodic
> palindromes". First of all, I think it would be good if these
> sequences either defined the term or clearly linked to a sequence with
> its definition.
It would be good to have a local copy of
M. R. Nester (1999).
Mathematical investigations of some plant interaction designs.
PhD Thesis. University of Queensland, Brisbane, Australia.
> Second, some are marked with keyword:base but in my
> understanding (possibly wrong) they are not base-dependent.
The keyword base shouldn't be there as far as I see.
> someone with more knowledge of this care to comment?
I assume the "aperiodic" refers to circular shifts,
e.g. A056458 Number of primitive (aperiodic) palindromes \
using a maximum of two different symbols
1: 0 and 1
2: none (palindromes are 11 and 00 but both are periodic)
3: 101 and 010 (111 and 000 are periodic)
4: 1001 and 0110
Obviously all terms are divisible by 2.
Similalry, all terms of A056459 are divisible by 3.
> Charles Greathouse
> Case Western Reserve University
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