A056510 Number of periodic palindromic structures of length n using exactly four different symbols.

0, 0, 0, 0, 0, 1, 1, 7, 10, 43, 65, 220, 350, 1059, 1701, 4803, 7770, 21105, 34105, 90248, 145750, 379391, 611501, 1573432, 2532530, 6465473, 10391745, 26379908, 42355950, 107091559, 171798901, 433093459, 694337290, 1746630985, 2798806985, 7029341790, 11259666950

Offset

1,8

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) = A056505(n) - A056504(n).

Inverse Moebius transform of A056521. - 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 4 of A285012.

Cf. A056473, A056504, A056505, A056521.

Sequence in context: A258284 A099579 A056521 * A013398 A013493 A166661

Adjacent sequences: A056507 A056508 A056509 * A056511 A056512 A056513

Keyword

nonn

Author

Marks R. Nester

Extensions

Corrected by T. D. Noe, Oct 25 2006

a(17)-a(30) from Andrew Howroyd, Apr 07 2017

Terms a(31) and beyond from Andrew Howroyd, Oct 01 2019

Status

approved