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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A130623 Number of polyhexes with perimeter at most 2n. 0
0, 0, 1, 1, 2, 3, 6, 8, 20, 34, 84, 182 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

The perimeter of a polyhex is always even. a(n) is partial sums of A057779(n) - Hexagonal polyominoes (or polyhexes, A000228) with perimeter 2n. a(2n+1) >= A131467(n) - Number of planar polyhexes (A000228) with at most n cells.

LINKS

Table of n, a(n) for n=0..11.

CROSSREFS

Cf. A038142 - Number of planar cata-polyhexes with n cells.

Sequence in context: A064450 A217137 A248824 * A072847 A274371 A095895

Adjacent sequences:  A130620 A130621 A130622 * A130624 A130625 A130626

KEYWORD

hard,more,nonn

AUTHOR

Tanya Khovanova, Aug 11 2007

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 April 28 16:04 EDT 2017. Contains 285578 sequences.