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Number of n X 5 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal, vertical or antidiagonal neighbor (colorings ignoring permutations of colors).
2

%I #9 Jun 25 2017 17:21:27

%S 15,4140,18171918,346212384169,18633407199331522,

%T 2254561102047453593406,531301410253869099621138608,

%U 220853044418109083337335323829443,150574889720989154216201888327789028154,159239694548038760947916228538237933340567164

%N Number of n X 5 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal, vertical or antidiagonal neighbor (colorings ignoring permutations of colors).

%H Andrew Howroyd, <a href="/A208053/b208053.txt">Table of n, a(n) for n = 1..50</a>

%e Some solutions for n=4

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

%e ..2..3..2..0..1....2..3..2..3..1....2..3..2..3..1....2..3..2..3..1

%e ..0..1..3..2..0....0..1..0..2..0....4..1..0..2..4....0..1..0..2..0

%e ..4..0..1..3..1....2..3..1..3..1....0..2..1..0..5....2..3..4..5..1

%Y Column 5 of A208054.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 22 2012

%E Terms a(6) and beyond from _Andrew Howroyd_, Jun 25 2017