A207865 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 or vertical neighbor (colorings ignoring permutations of colors).

2, 34, 2052, 278982, 68162042, 26419793726, 15002771641712, 11807624578397830, 12361734324171045410, 16679505289611340233906, 28284296659644702241447604, 59055088260515144420128767278, 149249218670114328150978145481610

Offset: 1

Author

R. H. Hardin, Feb 21 2012

Keywords

• nonn

Examples

			Some solutions for n=5
..0..1..2....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0
..2..0..1....1..0..1....1..0..1....1..0..1....1..0..2....1..0..1....1..2..1
..0..1..0....0..1..0....0..1..0....0..1..0....0..1..3....0..1..0....2..0..2
..1..0..1....1..0..1....1..0..1....1..2..1....1..0..1....2..0..1....0..1..0
..0..1..0....0..2..0....2..1..0....0..1..0....0..1..2....0..1..0....1..0..1
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..190 (terms 1..20 from R. H. Hardin)

Crossrefs

Column 3 of A207868.