login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A183324 Number of nX3 binary arrays with each 1 adjacent to exactly two other 1s 2
1, 3, 6, 10, 19, 37, 69, 129, 244, 460, 865, 1629, 3069, 5779, 10882, 20494, 38595, 72681, 136873, 257761, 485416, 914136, 1721505, 3241945, 6105241, 11497411, 21651966, 40775058, 76787731, 144606925, 272324269, 512842017, 965785884 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A183328

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n)=2*a(n-1)-a(n-2)+2*a(n-3)-a(n-4).

Empirical: G.f. -x*(-1-x+x^3-x^2) / ( 1-2*x+x^2-2*x^3+x^4 ), see A033305 - R. J. Mathar, Sep 27 2013

EXAMPLE

All solutions for 4X3

..0..0..0....0..0..0....1..1..1....0..0..0....0..0..0....0..0..0....1..1..0

..0..0..0....0..0..0....1..0..1....1..1..1....0..1..1....1..1..0....1..1..0

..1..1..0....0..0..0....1..0..1....1..0..1....0..1..1....1..1..0....0..0..0

..1..1..0....0..0..0....1..1..1....1..1..1....0..0..0....0..0..0....0..0..0

...

..0..0..0....0..1..1....1..1..1

..0..0..0....0..1..1....1..0..1

..0..1..1....0..0..0....1..1..1

..0..1..1....0..0..0....0..0..0

CROSSREFS

Sequence in context: A091714 A017991 A065614 * A058356 A270048 A295719

Adjacent sequences:  A183321 A183322 A183323 * A183325 A183326 A183327

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 03 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 19 18:35 EDT 2022. Contains 353847 sequences. (Running on oeis4.)