

A056515


Number of primitive (period n) periodic palindromic structures using a maximum of four different symbols.


5



1, 1, 1, 1, 3, 4, 10, 14, 35, 49, 127, 186, 463, 714, 1799, 2789, 6996, 11050, 27685, 43946, 109925, 175259, 438495, 700074, 1750445, 2798246, 6996927, 11188856, 27973533, 44747434, 111873782, 178973354, 447438656, 715860463, 1789673215, 2863377048, 7158463662
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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_{dn} mu(d)*A056505(n/d) for n > 0.
Moebius transform of A056505.
a(n) = Sum_{k=1..4} A285037(n, k) for n > 0.  Andrew Howroyd, Oct 01 2019


CROSSREFS

Cf. A056478, A056505, A285037.
Sequence in context: A106523 A007068 A121720 * A056516 A056517 A285042
Adjacent sequences: A056512 A056513 A056514 * A056516 A056517 A056518


KEYWORD

nonn


AUTHOR

Marks R. Nester


EXTENSIONS

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


STATUS

approved



