login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A056521 Number of primitive (period n) periodic palindromic structures using exactly four different symbols. 4
0, 0, 0, 0, 0, 1, 1, 7, 10, 43, 65, 219, 350, 1058, 1701, 4796, 7770, 21094, 34105, 90205, 145749, 379326, 611501, 1573205, 2532530, 6465123, 10391735, 26378849, 42355950, 107089814, 171798901, 433088656, 694337225, 1746623215, 2798806984, 7029320466, 11259666950 (list; graph; refs; listen; history; text; internal format)
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) = A056515(n) - A056514(n).

Moebius transform of A056510. - T. D. Noe, Oct 25 2006

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 A285037.

Cf. A056483, A056510, A056514, A056515.

Sequence in context: A126076 A258284 A099579 * A056510 A013398 A013493

Adjacent sequences:  A056518 A056519 A056520 * A056522 A056523 A056524

KEYWORD

nonn

AUTHOR

Marks R. Nester

EXTENSIONS

Corrected by T. D. Noe, Oct 25 2006

a(17)-a(30) from Andrew Howroyd, Apr 08 2017

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 23 12:54 EDT 2019. Contains 328345 sequences. (Running on oeis4.)