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A234826 Number of (n+1) X (2+1) 0..2 arrays with each 2 X 2 subblock having the number of clockwise edge increases less than or equal to the number of counterclockwise edge increases. 1
516, 9207, 161631, 2826144, 49366557, 862112943, 15054585588, 262885602843, 4590533340099, 80160252775488, 1399764282940233, 24442786354729203, 426821718006927396, 7453191942015413679, 130148180682091274007 (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) = 23*a(n-1) - 102*a(n-2) + 93*a(n-3) - 9*a(n-4).

Empirical g.f.: 3*x*(172 - 887*x + 834*x^2 - 81*x^3) / (1 - 23*x + 102*x^2 - 93*x^3 + 9*x^4). - Colin Barker, Oct 16 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

CROSSREFS

Column 2 of A234832.

Sequence in context: A254643 A322883 A332151 * A232574 A282753 A168188

Adjacent sequences:  A234823 A234824 A234825 * A234827 A234828 A234829

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 31 2013

STATUS

approved

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Last modified September 24 12:45 EDT 2022. Contains 356932 sequences. (Running on oeis4.)