A056517 Number of primitive (period n) periodic palindromic structures using a maximum of six different symbols.

1, 1, 1, 1, 3, 4, 10, 14, 36, 50, 138, 202, 561, 875, 2571, 4105, 12548, 20647, 65456, 109298, 356466, 601476, 2005341, 3403126, 11522216, 19628059, 67182654, 114700263, 395494722, 676207627, 2343260789, 4010090462, 13942474064, 23874361996, 83192218842, 142508723632

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)*A056507(n/d) for n > 0.

a(n) = Sum_{k=1..6} A285037(n, k) for n > 0. - Andrew Howroyd, Oct 01 2019

Crossrefs

Cf. A056480, A056507, A285037.

Sequence in context: A121720 A056515 A056516 * A285042 A319719 A347568

Adjacent sequences: A056514 A056515 A056516 * A056518 A056519 A056520

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