A208019 - OEIS

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).

%I #8 Jun 25 2017 17:13:51

%S 5,87,27093,30066912,80318704605,421673189900658,3840411377316733859,

%T 55738840149772892317910,1212109474086951274342594323,

%U 37684550247867169399313491413883,1614317526939802578784333734266333582,92481709137707355217408169152041892948306

%N 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).

%H Andrew Howroyd, <a href="/A208019/b208019.txt">Table of n, a(n) for n = 1..50</a>

%e Some solutions for n=4

%e ..0..1..2..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1

%e ..2..3..0..3....2..3..2..3....2..3..2..3....2..3..2..3....2..3..2..3

%e ..0..4..1..2....4..0..5..0....0..1..0..1....0..1..0..4....0..1..4..0

%e ..1..2..3..4....1..2..3..1....4..2..3..5....2..3..2..1....2..3..2..1

%Y Column 4 of A208021.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 22 2012

%E Terms a(8) and beyond from _Andrew Howroyd_, Jun 25 2017