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A056506 Number of periodic palindromic structures using a maximum of five different symbols. 5
1, 1, 2, 2, 5, 5, 13, 15, 41, 52, 143, 202, 564, 855, 2433, 3845, 11101, 18002, 52662, 86472, 255128, 422005, 1252898, 2079475, 6197590, 10306752, 30796243, 51263942, 153411664, 255514355, 765393943, 1275163905, 3822001141, 6368612302, 19095317552, 31821472612 (list; graph; refs; listen; history; text; internal format)
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..5} A285012(n, k) for n > 0. - Andrew Howroyd, Oct 01 2019

CROSSREFS

Cf. A056470, A285012.

Sequence in context: A322111 A321395 A056505 * A056507 A285013 A095014

Adjacent sequences:  A056503 A056504 A056505 * A056507 A056508 A056509

KEYWORD

nonn

AUTHOR

Marks R. Nester

EXTENSIONS

Corrected by T. D. Noe, Oct 25 2006

a(0)=1 prepended and terms a(17) and beyond from Andrew Howroyd, Oct 01 2019

STATUS

approved

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Last modified November 12 19:33 EST 2019. Contains 329078 sequences. (Running on oeis4.)