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!)
A262414 Number of (n+1) X (2+1) 0..1 arrays with each row divisible by 3 and column not divisible by 3, read as a binary number with top and left being the most significant bits. 1
0, 4, 12, 48, 144, 468, 1404, 4320, 12960, 39204, 117612, 353808, 1061424, 3187188, 9561564, 28693440, 86080320, 258267204, 774801612, 2324483568, 6973450704, 20920588308, 62761764924, 188286003360, 564858010080, 1694576156004 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + 3*a(n-2) - 9*a(n-3).

Empirical g.f.: 4*x^2 / ((1 - 3*x)*(1 - 3*x^2)). - Colin Barker, Dec 31 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 2 of A262420.

Sequence in context: A057346 A255230 A253087 * A081620 A282023 A149376

Adjacent sequences:  A262411 A262412 A262413 * A262415 A262416 A262417

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 22 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 September 21 20:10 EDT 2021. Contains 347598 sequences. (Running on oeis4.)