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 A056516 Number of primitive (period n) periodic palindromic structures using a maximum of five different symbols. 4
 1, 1, 1, 1, 3, 4, 10, 14, 36, 50, 137, 201, 548, 854, 2417, 3839, 11060, 18001, 52599, 86471, 254982, 421989, 1252695, 2079474, 6196990, 10306747, 30795387, 51263890, 153409228, 255514354, 765389950, 1275163904, 3821990040, 6368612099, 19095299549, 31821472593 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 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_{d|n} mu(d)*A056506(n/d) for n > 0. Moebius transform of A056506. - T. D. Noe, Oct 25 2006 a(n) = Sum_{k=1..5} A285037(n, k) for n > 0. - Andrew Howroyd, Oct 01 2019 CROSSREFS Cf. A056479, A056506, A285037. Sequence in context: A007068 A121720 A056515 * A056517 A285042 A319719 Adjacent sequences:  A056513 A056514 A056515 * A056517 A056518 A056519 KEYWORD nonn AUTHOR 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 February 23 04:49 EST 2020. Contains 332159 sequences. (Running on oeis4.)