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

Offset: 0

Author

R. H. Hardin, Feb 25 2012

Keywords

• nonn

Examples

			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
		

Links

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

Crossrefs

Row 3 of A208301.

Extensions

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