A056507 Number of periodic palindromic structures using a maximum of six different symbols.

1, 1, 2, 2, 5, 5, 13, 15, 41, 52, 144, 203, 577, 876, 2587, 4111, 12589, 20648, 65519, 109299, 356613, 601492, 2005545, 3403127, 11522829, 19628064, 67183531, 114700315, 395497312, 676207628, 2343265049, 4010090463, 13942486653, 23874362200, 83192239491, 142508723651

Offset

0,3

Comments

For example, aaabbb is not a (finite) palindrome but it is a periodic palindrome. Permuting the symbols will not change the structure.

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

Andrew Howroyd, Table of n, a(n) for n = 0..200

Formula

a(n) = Sum_{k=1..6} A285012(n, k) for n > 0. - Andrew Howroyd, Oct 01 2019

Crossrefs

Cf. A056471, A285012.

Sequence in context: A321395 A056505 A056506 * A285013 A095014 A129996

Adjacent sequences: A056504 A056505 A056506 * A056508 A056509 A056510

Keyword

nonn

Author

Marks R. Nester

Extensions

Corrected by T. D. Noe, Oct 25 2006

a(0)=1 prepended and terms a(16) and beyond from Andrew Howroyd, Oct 01 2019

Status

approved