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A280393 Number of n X 3 0..2 arrays with no element unequal 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
2, 6, 66, 554, 4250, 31242, 223706, 1571978, 10887706, 74545802, 505624538, 3402833418, 22750442266, 151248129802, 1000625900506, 6591782458762, 43261686405658, 282980475181450, 1845507292321242, 12003609559311114 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 18*a(n-1) - 121*a(n-2) + 392*a(n-3) - 688*a(n-4) + 640*a(n-5) - 256*a(n-6) for n>7.

Empirical g.f.: 2*x*(1 - 2*x)*(1 - 13*x + 74*x^2 - 198*x^3 + 248*x^4 - 128*x^5) / (1 - 9*x + 20*x^2 - 16*x^3)^2. - Colin Barker, Feb 13 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 3 of A280398.

Sequence in context: A070872 A055685 A262047 * A239696 A335645 A082619

Adjacent sequences:  A280390 A280391 A280392 * A280394 A280395 A280396

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 02 2017

STATUS

approved

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Last modified January 27 22:20 EST 2022. Contains 350654 sequences. (Running on oeis4.)