

A279851


Number of n X 2 0..2 arrays with no element unequal to a strict majority of its horizontal and vertical neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.


1



0, 4, 10, 24, 54, 116, 250, 528, 1118, 2348, 4930, 10312, 21542, 44900, 93450, 194176, 402926, 834972, 1728210, 3572920, 7378870, 15223764, 31379610, 64623344, 132974974, 273406476, 561726050, 1153278248, 2366208838, 4851722308
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OFFSET

1,2


LINKS

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


FORMULA

Empirical: a(n) = 3*a(n1) + a(n2)  7*a(n3) + 4*a(n5).
Empirical g.f.: 2*x^2*(2  x  5*x^2) / ((1  x)*(1 + x)^2*(1  2*x)^2).  Colin Barker, Feb 12 2019


EXAMPLE

Some solutions for n=4:
..0..1. .0..1. .0..0. .0..1. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0
..0..0. .0..1. .0..1. .0..0. .1..1. .0..0. .0..1. .1..0. .0..0. .1..0
..0..0. .1..1. .0..0. .0..0. .1..1. .0..0. .0..1. .0..0. .0..1. .1..0
..1..1. .1..1. .0..0. .2..2. .1..2. .0..1. .0..1. .0..0. .0..0. .1..0


CROSSREFS

Column 2 of A279856.
Sequence in context: A080615 A173729 A097976 * A266367 A316528 A152548
Adjacent sequences: A279848 A279849 A279850 * A279852 A279853 A279854


KEYWORD

nonn


AUTHOR

R. H. Hardin, Dec 20 2016


STATUS

approved



