login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A056523
Number of primitive (period n) periodic palindromic structures using exactly six different symbols.
3
0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 13, 21, 154, 266, 1488, 2646, 12857, 22827, 101484, 179487, 752646, 1323652, 5325226, 9321312, 36387267, 63436373, 242085494, 420693273, 1577870839, 2734926558, 10120484024, 17505749897, 64096919293, 110687251039, 401885411487
OFFSET
1,12
REFERENCES
M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]
LINKS
FORMULA
a(n) = A056517(n) - A056516(n).
Moebius transform of A056512. - Andrew Howroyd, Oct 01 2019
EXAMPLE
For example, aaabbb is not a (finite) palindrome but it is a periodic palindrome. Permuting the symbols will not change the structure. This should be different from A056512.
CROSSREFS
Column 6 of A285037.
Sequence in context: A269309 A203854 A325448 * A056512 A362098 A158998
KEYWORD
nonn
EXTENSIONS
a(16)-a(26) from Andrew Howroyd, Apr 09 2017
Terms a(27) and beyond from Andrew Howroyd, Oct 01 2019
STATUS
approved