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 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). 2
 5, 87, 27093, 30066912, 80318704605, 421673189900658, 3840411377316733859, 55738840149772892317910, 1212109474086951274342594323, 37684550247867169399313491413883, 1614317526939802578784333734266333582, 92481709137707355217408169152041892948306 (list; graph; refs; listen; history; text; internal format)
 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

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Last modified May 17 08:05 EDT 2022. Contains 353741 sequences. (Running on oeis4.)