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A280392 Number of nX2 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
0, 2, 14, 74, 358, 1666, 7582, 33978, 150486, 660210, 2873870, 12427562, 53438534, 228667234, 974321278, 4135894426, 17498014902, 73809808338, 310510228206, 1303124892170, 5456835485990, 22804685613122, 95128117129054 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A280398.

LINKS

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

FORMULA

Empirical: a(n) = 10*a(n-1) -33*a(n-2) +40*a(n-3) -16*a(n-4).

Empirical: a(n) = 4^n*n/18 -4*n/9 +2*4^n/27 -2/27. - R. J. Mathar, Jan 04 2017

Empirical g.f.: -2*x^2*(-1+3*x) / ( (4*x-1)^2*(x-1)^2 ). - R. J. Mathar, Jan 04 2017

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Cf. A280398.

Sequence in context: A043011 A290698 A138156 * A192809 A198762 A119913

Adjacent sequences:  A280389 A280390 A280391 * A280393 A280394 A280395

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 02 2017

STATUS

approved

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Last modified November 20 05:07 EST 2019. Contains 329323 sequences. (Running on oeis4.)