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A233942 Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock having the sum of the absolute values of the edge differences equal to 4. 1
44, 226, 1150, 5874, 29970, 152974, 780718, 3984650, 20336682, 103793974, 529740902, 2703678866, 13798968738, 70426836510, 359442745310, 1834515000218, 9362952299866, 47786404483974, 243891069807254, 1244765212590370 (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) = 5*a(n-1) + 3*a(n-2) - 13*a(n-3) + 2*a(n-4).

Empirical g.f.: 2*x*(22 + 3*x - 56*x^2 + 9*x^3) / (1 - 5*x - 3*x^2 + 13*x^3 - 2*x^4). - Colin Barker, Oct 12 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

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

CROSSREFS

Column 1 of A233949.

Sequence in context: A250454 A250447 A233949 * A122245 A031175 A098826

Adjacent sequences:  A233939 A233940 A233941 * A233943 A233944 A233945

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 18 2013

STATUS

approved

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Last modified May 17 12:55 EDT 2021. Contains 343971 sequences. (Running on oeis4.)