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A318010 Number of nX2 0..1 arrays with every element unequal to 0, 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 2
2, 8, 28, 97, 338, 1178, 4105, 14305, 49850, 173717, 605368, 2109583, 7351463, 25618337, 89274637, 311103754, 1084132616, 3777979256, 13165480909, 45878993986, 159878860766, 557144956745, 1941535618525, 6765852427390 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A318016.

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) -2*a(n-2) +a(n-3) -a(n-4)

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A318016.

Sequence in context: A280279 A060995 A106731 * A291383 A277653 A066796

Adjacent sequences:  A318007 A318008 A318009 * A318011 A318012 A318013

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 12 2018

STATUS

approved

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Last modified May 31 09:30 EDT 2020. Contains 334748 sequences. (Running on oeis4.)