A208019 Number of n X 4 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).

5, 87, 27093, 30066912, 80318704605, 421673189900658, 3840411377316733859, 55738840149772892317910, 1212109474086951274342594323, 37684550247867169399313491413883, 1614317526939802578784333734266333582, 92481709137707355217408169152041892948306

Offset: 1

Author

R. H. Hardin, Feb 22 2012

Keywords

• nonn

Examples

			Some solutions for n=4
..0..1..2..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
..2..3..0..3....2..3..2..3....2..3..2..3....2..3..2..3....2..3..2..3
..0..4..1..2....4..0..5..0....0..1..0..1....0..1..0..4....0..1..4..0
..1..2..3..4....1..2..3..1....4..2..3..5....2..3..2..1....2..3..2..1
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..50

Crossrefs

Column 4 of A208021.

Extensions

Terms a(8) and beyond from Andrew Howroyd, Jun 25 2017