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!)
A259291 Number of (n+1) X (2+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0001 0101 or 0111. 1
26, 94, 322, 1134, 3938, 13774, 48002, 167598, 584610, 2040206, 7118274, 24838766, 86667746, 302412110, 1055197186, 3681898030, 12847185954, 44827572494, 156416277058, 545781633518, 1904389428834, 6644964604110, 23186198459522 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 3*a(n-1) + 4*a(n-2) - 8*a(n-3).

Empirical g.f.: 2*x*(13 + 8*x - 32*x^2) / (1 - 3*x - 4*x^2 + 8*x^3). - Colin Barker, Dec 25 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 2 of A259297.

Sequence in context: A044594 A205998 A205991 * A038654 A010014 A095796

Adjacent sequences:  A259288 A259289 A259290 * A259292 A259293 A259294

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 23 2015

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 June 19 15:47 EDT 2021. Contains 345142 sequences. (Running on oeis4.)