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A279866 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 two elements, and with new values introduced in order 0 sequentially upwards. 1
1, 4, 33, 96, 255, 610, 1437, 3292, 7451, 16662, 36921, 81200, 177399, 385450, 833365, 1794180, 3848019, 8225214, 17528049, 37250392, 78966831, 167021394, 352528653, 742650796, 1561730955, 3278806630, 6873273257, 14387809152, 30078027111 (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) = 5*a(n-1) - 4*a(n-2) - 14*a(n-3) + 19*a(n-4) + 13*a(n-5) - 22*a(n-6) - 4*a(n-7) + 8*a(n-8) for n>9.

Empirical g.f.: x*(1 - x + 17*x^2 - 39*x^3 - 56*x^4 + 92*x^5 + 94*x^6 - 44*x^7 - 80*x^8) / ((1 - x)^2*(1 + x)^3*(1 - 2*x)^3). - Colin Barker, Feb 12 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 2 of A279871.

Sequence in context: A042831 A092207 A133630 * A066645 A295939 A297515

Adjacent sequences:  A279863 A279864 A279865 * A279867 A279868 A279869

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 21 2016

STATUS

approved

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Last modified August 3 20:08 EDT 2020. Contains 336201 sequences. (Running on oeis4.)