A056519 - OEIS

A056519

Number of primitive (period n) periodic palindromic structures using exactly three different symbols.

0, 0, 0, 1, 1, 5, 6, 18, 25, 63, 90, 202, 301, 650, 965, 2016, 3025, 6220, 9330, 18970, 28495, 57650, 86526, 174210, 261624, 525693, 788945, 1582462, 2375101, 4759482, 7141686, 14300976, 21457735, 42951825, 64439003, 128946888, 193448101, 387037370, 580606145, 1161485370

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,6

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 = 1..200

FORMULA

a(n) = A056514(n) - A056513(n).

Moebius transform of A056509. - Andrew Howroyd, Oct 01 2019

EXAMPLE

For example, aaabbb is not a (finite) palindrome but it is a periodic palindrome. Permuting the symbols will not change the structure.

CROSSREFS

Column 3 of A285037.

Cf. A056482, A056509, A056513, A056514.

Sequence in context: A041747 A180134 A192727 * A295972 A333405 A063445

Adjacent sequences: A056516 A056517 A056518 * A056520 A056521 A056522