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.

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

Offset

1,2

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + a(n-2) - 7*a(n-3) + 4*a(n-5).

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: A173729 A340569 A097976 * A266367 A316528 A152548

Adjacent sequences: A279848 A279849 A279850 * A279852 A279853 A279854

Keyword

nonn

Author

R. H. Hardin, Dec 20 2016

Status

approved