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A232290 Number of n X 3 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or antidiagonally.

%I A232290 #8 Oct 04 2018 11:50:36
%S A232290 7,97,1313,17759,240241,3249889,43963319,594719777,8045152705,
%T A232290 108831897871,1472238306545,19915904010305,269415101335399,
%U A232290 3644549440989793,49302138454678241,666941386187953343
%N A232290 Number of n X 3 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or antidiagonally.
%H A232290 R. H. Hardin, <a href="/A232290/b232290.txt">Table of n, a(n) for n = 1..210</a>
%F A232290 Empirical: a(n) = 12*a(n-1) + 20*a(n-2) + 9*a(n-3).
%F A232290 Empirical g.f.: x*(7 + 13*x + 9*x^2) / (1 - 12*x - 20*x^2 - 9*x^3). - _Colin Barker_, Oct 04 2018
%e A232290 Some solutions for n=4:
%e A232290 ..1..2..0....1..2..2....1..2..2....0..1..0....0..1..0....2..1..2....2..2..2
%e A232290 ..1..1..2....2..1..2....2..1..0....2..2..2....2..2..1....2..1..2....0..1..0
%e A232290 ..0..1..1....0..2..2....2..1..0....0..1..0....0..1..2....2..2..2....0..2..0
%e A232290 ..1..2..1....2..1..2....2..2..1....0..1..2....0..2..1....1..2..2....2..1..0
%Y A232290 Column 3 of A232295.
%K A232290 nonn
%O A232290 1,1
%A A232290 _R. H. Hardin_, Nov 22 2013