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

1,1

Links

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

Example

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

Crossrefs

Column 4 of A208021.

Sequence in context: A216088 A305001 A324092 * A297529 A300135 A221465

Adjacent sequences: A208016 A208017 A208018 * A208020 A208021 A208022

Keyword

nonn

Author

R. H. Hardin, Feb 22 2012

Extensions

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

Status

approved