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A279574 Number of n X 2 0..2 arrays with no element equal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards. 1
0, 4, 40, 352, 3008, 25280, 209792, 1723392, 14039040, 113562624, 913131520, 7304519680, 58170228736, 461421658112, 3647369216000, 28741570396160, 225854805245952, 1770332698705920, 13844879799484416, 108048964894326784 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = 16*a(n-1) - 72*a(n-2) + 64*a(n-3) - 16*a(n-4).

Empirical g.f.: 4*x^2*(1 - 6*x) / (1 - 8*x + 4*x^2)^2. - Colin Barker, Feb 11 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 2 of A279580.

Sequence in context: A145730 A069721 A223176 * A327675 A191681 A222273

Adjacent sequences:  A279571 A279572 A279573 * A279575 A279576 A279577

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 15 2016

STATUS

approved

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Last modified October 15 22:25 EDT 2019. Contains 328038 sequences. (Running on oeis4.)