

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
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OFFSET

1,2


LINKS

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


FORMULA

Empirical: a(n) = 16*a(n1)  72*a(n2) + 64*a(n3)  16*a(n4).
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



