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%I #8 Jan 31 2019 08:06:33
%S 2,9,19,43,100,233,542,1260,2929,6809,15829,36798,85545,198868,462312,
%T 1074745,2498479,5808259,13502564,31389653,72972090,169639528,
%U 394364057,916785205,2131267029,4954594734,11518035349,26776183608,62247074860
%N Number of n X 3 0..2 arrays with no element equal to any value at offset (-1,0) (0,-1) or (-2,-2) and new values introduced in order 0..2.
%H R. H. Hardin, <a href="/A274853/b274853.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) - 2*a(n-2) + a(n-3) for n>4.
%F Empirical g.f.: x*(2 + 3*x - 4*x^2 + 2*x^3) / (1 - 3*x + 2*x^2 - x^3). - _Colin Barker_, Jan 31 2019
%e Some solutions for n=4:
%e ..0..1..0. .0..1..2. .0..1..0. .0..1..0. .0..1..2. .0..1..0. .0..1..2
%e ..1..2..1. .1..2..0. .1..2..1. .2..0..1. .1..2..0. .2..0..2. .1..2..0
%e ..2..0..2. .2..0..1. .0..1..2. .0..1..2. .0..1..2. .0..2..1. .2..1..2
%e ..0..2..0. .0..1..2. .1..2..0. .1..2..1. .1..2..0. .2..1..0. .1..2..0
%Y Column 3 of A274858.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jul 09 2016
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