A208303 - OEIS

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A208303

Number of 3 X n nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors).

1, 5, 52, 2906, 373780, 87852626, 33093356640, 18383354934430, 14216420560211868, 14670987603972303070, 19558496205580909812744, 32828323774419481541135978, 67939294184199439807451132308, 170381709310740181061939305134514, 510275358861788633812686061715278224

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..100

EXAMPLE

Some solutions for n=4:

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

..2..1..2..0....0..1..0..1....3..1..0..2....0..1..0..1....3..0..1..0

..0..3..1..0....0..1..2..1....0..1..0..1....2..1..2..0....1..0..3..0

CROSSREFS

Row 3 of A208301.

Sequence in context: A001173 A277202 A223248 * A215902 A215846 A216459

Adjacent sequences: A208300 A208301 A208302 * A208304 A208305 A208306

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 25 2012

EXTENSIONS

a(0)=1 prepended and terms a(10) and beyond from Andrew Howroyd, May 18 2020

STATUS

approved