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A208018 Number of n X 3 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal, vertical, diagonal or antidiagonal neighbor (colorings ignoring permutations of colors). 2
2, 7, 270, 27093, 5252041, 1688298227, 819147302097, 562766251199622, 522687453434959180, 633631710314384052082, 975235769907492737264795, 1863659976446678796423595540, 4341202639797991970260869847084, 12137362722177750192276998364963783 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..100

EXAMPLE

Some solutions for n=4

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

..2..3..2....2..3..2....2..3..2....2..3..0....2..3..2....2..3..4....2..3..2

..4..0..4....0..1..0....4..1..0....4..5..4....0..1..0....5..6..0....0..1..0

..1..2..1....2..3..2....5..2..3....0..1..2....2..3..4....2..3..1....3..2..3

CROSSREFS

Column 3 of A208021.

Sequence in context: A295610 A329967 A012942 * A013058 A013097 A037067

Adjacent sequences:  A208015 A208016 A208017 * A208019 A208020 A208021

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 22 2012

EXTENSIONS

Terms a(14) and beyond from Andrew Howroyd, Jun 25 2017

STATUS

approved

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Last modified May 19 15:00 EDT 2022. Contains 353834 sequences. (Running on oeis4.)