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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A208485 Number of (n+1) X 2 0..3 arrays with the number of clockwise edge increases in every 2 X 2 subblock equal to the number of counterclockwise edge increases. 1
152, 1448, 13800, 131528, 1253608, 11948296, 113880744, 1085412040, 10345202024, 98601453704, 939783162408, 8957194434632, 85372174507240, 813693197494792, 7755414729341352, 73917857257827784, 704520623625326696 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A208492.

LINKS

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

FORMULA

Empirical: a(n) = 11*a(n-1) - 14*a(n-2).

Empirical g.f.: 8*x*(19 - 28*x) / (1 - 11*x + 14*x^2). - Colin Barker, Jul 03 2018

EXAMPLE

Some solutions for n=4:

..3..2....2..3....1..1....3..1....1..0....1..1....2..1....2..0....1..0....1..3

..3..2....0..1....2..2....3..1....2..1....3..1....1..0....3..1....0..0....2..0

..1..3....2..0....1..1....3..3....1..2....0..2....3..1....2..0....0..3....0..2

..0..1....0..1....0..0....3..1....1..1....1..0....0..2....3..1....1..0....2..1

..0..0....3..0....0..0....1..1....0..0....2..1....0..0....1..2....1..0....1..0

CROSSREFS

Cf. A208492.

Sequence in context: A226365 A085775 A208492 * A223397 A239065 A229418

Adjacent sequences:  A208482 A208483 A208484 * A208486 A208487 A208488

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 27 2012

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 December 6 01:25 EST 2021. Contains 349558 sequences. (Running on oeis4.)