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A281133 Number of n X 2 0..2 arrays with no element equal to more than one of its king-move neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards. 1
0, 0, 24, 112, 504, 2528, 11712, 52160, 230048, 1000320, 4294016, 18264832, 77098880, 323290624, 1347997696, 5593390080, 23110676992, 95130810368, 390287108096, 1596449140736, 6512744568832, 26504685772800, 107628465111040 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-1) - 20*a(n-2) + 32*a(n-3) - 84*a(n-4) + 96*a(n-5) - 96*a(n-6) + 128*a(n-7) - 64*a(n-8).

Empirical g.f.: 8*x^3*(1 - x)^2*(3 - 4*x) / (1 - 4*x + 2*x^2 - 8*x^3 + 8*x^4)^2. - Colin Barker, Feb 16 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 2 of A281139.

Sequence in context: A162451 A307859 A263542 * A064595 A064591 A228433

Adjacent sequences:  A281130 A281131 A281132 * A281134 A281135 A281136

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 15 2017

STATUS

approved

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Last modified November 17 23:26 EST 2019. Contains 329242 sequences. (Running on oeis4.)