A056478 Number of primitive (aperiodic) palindromic structures using a maximum of four different symbols.

1, 1, 0, 1, 1, 4, 3, 14, 13, 49, 46, 186, 181, 714, 700, 2789, 2780, 11050, 10997, 43946, 43895, 175259, 175088, 700074, 699875, 2798246, 2797536, 11188856, 11188191, 44747434, 44744591, 178973354, 178970560, 715860463, 715849600, 2863377048, 2863365834

Offset

0,6

Comments

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..500

Formula

a(n) = Sum_{d|n} mu(d)*A124303(ceiling(n/(2*d))) for n > 0.

a(n) = Sum_{k=1..4} A284826(n, k) for n > 0. - Andrew Howroyd, Oct 02 2019

Crossrefs

Cf. A007581, A124303, A056460, A284826.

Sequence in context: A082383 A216486 A321262 * A056479 A056480 A284841

Adjacent sequences: A056475 A056476 A056477 * A056479 A056480 A056481

Keyword

nonn

Author

Marks R. Nester

Extensions

a(0)=1 prepended and terms a(32) and beyond from Andrew Howroyd, Oct 02 2019

Status

approved