login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A184408 Number of holes in the toothpick structure of A182840. 3
0, 0, 0, 0, 0, 0, 0, 2, 6, 6, 6, 6, 6, 8, 12, 18, 30, 30, 30, 30, 30, 30, 30, 34, 46, 56, 60, 60, 60, 66, 80, 98, 126, 126, 126, 126, 126, 126, 126, 130, 142, 150, 150, 150, 150, 154, 166, 186, 222, 248, 252, 252, 252, 252, 252, 260, 288, 322, 344, 348, 348, 364, 404, 450, 510, 510, 510, 510, 510, 510, 510, 514, 526 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,8

COMMENTS

Each connected group of unoccupied lines in the hexagonal structure enclosed by toothpicks counts as a hole.

LINKS

Olaf Voß, Table of n, a(n) for n = 0..625

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

Olaf Voß, Toothpick structures on hexagonal net

Index entries for sequences related to toothpick sequences

EXAMPLE

Structure after step 8:

      \_/

    \_/ \_/

  \_/ \_/ \_/

\_/  _/ \_  \_/

/ \_/ \_/ \_/ \

\_/ \_/ \_/ \_/

/ \ / \_/ \ / \

\_/ \_/ \_/ \_/

/ \_/ \_/ \_/ \

\_/ \_/ \_/ \_/

/ \_  \_/  _/ \

  / \_/ \_/ \

    / \_/ \

      / \

There are 6 holes in this structure, so a(8)=6.

CROSSREFS

For total number of missing toothpicks see A184409.

Sequence in context: A141624 A134413 A134201 * A184409 A137479 A304363

Adjacent sequences:  A184405 A184406 A184407 * A184409 A184410 A184411

KEYWORD

nonn

AUTHOR

Olaf Voß, Jan 13 2011

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 July 26 20:17 EDT 2021. Contains 346294 sequences. (Running on oeis4.)