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A300345 Number of nX3 0..1 arrays with every element equal to 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 1
1, 6, 9, 26, 57, 133, 306, 709, 1642, 3805, 8811, 20409, 47276, 109514, 253686, 587661, 1361316, 3153496, 7305099, 16922333, 39200767, 90809027, 210360189, 487301922, 1128840861, 2614973750, 6057619008, 14032549467, 32506574899, 75301884294 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A300350.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +a(n-2) -2*a(n-5) -2*a(n-6) -2*a(n-7) -a(n-8) for n>10

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A300350.

Sequence in context: A260565 A115644 A243708 * A024878 A007414 A274977

Adjacent sequences:  A300342 A300343 A300344 * A300346 A300347 A300348

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 03 2018

STATUS

approved

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Last modified August 5 07:54 EDT 2021. Contains 346464 sequences. (Running on oeis4.)