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A281600 Number of n X 3 0..2 arrays with no element equal to more than one of its horizontal, diagonal or antidiagonal neighbors and with new values introduced in order 0 sequentially upwards. 1
4, 29, 209, 1623, 12413, 95623, 736757, 5678559, 43771933, 337417047, 2601018757, 20050333455, 154561132461, 1191459205767, 9184555212821, 70800627012031, 545778076046781, 4207218532446903, 32432024283432101, 250007502993994607 (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) = 7*a(n-1) + 10*a(n-2) - 26*a(n-3) - 64*a(n-4) - 40*a(n-5) for n>6.

Empirical g.f.: x*(4 + x - 34*x^2 - 26*x^3 - 28*x^4 - 48*x^5) / (1 - 7*x - 10*x^2 + 26*x^3 + 64*x^4 + 40*x^5). - Colin Barker, Feb 20 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 3 of A281605.

Sequence in context: A288913 A100022 A001883 * A135429 A079756 A344098

Adjacent sequences:  A281597 A281598 A281599 * A281601 A281602 A281603

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 25 2017

STATUS

approved

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Last modified December 8 20:37 EST 2021. Contains 349596 sequences. (Running on oeis4.)