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A279651 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 two elements, and with new values introduced in order 0 sequentially upwards. 1
1, 3, 24, 232, 2232, 20880, 190656, 1707264, 15046272, 130854656, 1125285888, 9583835136, 80941029376, 678574706688, 5651894845440, 46802046418944, 385539453517824, 3161014415327232, 25806384396763136, 209862489033670656 (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) = 24*a(n-1) - 204*a(n-2) + 704*a(n-3) - 816*a(n-4) + 384*a(n-5) - 64*a(n-6) for n>7.

Empirical g.f.: x*(1 - 21*x + 156*x^2 - 436*x^3 + 264*x^4 - 192*x^5 + 32*x^6) / (1 - 8*x + 4*x^2)^3. - Colin Barker, Feb 11 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 2 of A279657.

Sequence in context: A307514 A225107 A249926 * A001099 A277462 A230325

Adjacent sequences:  A279648 A279649 A279650 * A279652 A279653 A279654

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 16 2016

STATUS

approved

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Last modified May 20 03:10 EDT 2019. Contains 323412 sequences. (Running on oeis4.)