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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A030228 Number of n-celled polyominoes without bilateral symmetry. 3
0, 0, 0, 2, 6, 25, 88, 335, 1215, 4534, 16823, 63159, 237679, 900341, 3423201, 13073163, 50095285, 192599091, 742576616, 2870584814, 11122879867, 43191525139 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

A000105(n) + a(n) = A000988(n) because the number of free polyominoes plus the number of polyominoes lacking bilateral symmetry equals the number of one-sided polyominoes. - Graeme McRae, Jan 05 2006

LINKS

Table of n, a(n) for n=1..22.

CROSSREFS

Sequence in context: A073545 A103063 A220191 * A066317 A027104 A019048

Adjacent sequences:  A030225 A030226 A030227 * A030229 A030230 A030231

KEYWORD

nonn

AUTHOR

David W. Wilson

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 20 16:14 EST 2018. Contains 299380 sequences. (Running on oeis4.)