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A232336 Number of 2 X n 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or antidiagonally, with no adjacent elements equal.

%I A232336 #8 Oct 04 2018 11:51:54
%S A232336 1,6,18,32,82,162,388,806,1858,3968,8962,19426,43396,94822,210578,
%T A232336 462112,1022994,2250178,4972804,10951878,24180994,53291008,117604738,
%U A232336 259275842,572028164,1261360966,2782483346,6136209184,13535050578,29850527586
%N A232336 Number of 2 X n 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or antidiagonally, with no adjacent elements equal.
%H A232336 R. H. Hardin, <a href="/A232336/b232336.txt">Table of n, a(n) for n = 1..210</a>
%F A232336 Empirical: a(n) = a(n-1) + 3*a(n-2) - a(n-3) + a(n-4) - a(n-5) for n>6.
%F A232336 Empirical g.f.: x*(1 + 5*x + 9*x^2 - 3*x^3 + x^4 - 3*x^5) / ((1 + x - x^2)*(1 - 2*x - x^3)). - _Colin Barker_, Oct 04 2018
%e A232336 Some solutions for n=7:
%e A232336 ..2..0..1..0..2..1..0....2..1..2..1..0..2..1....1..2..1..0..2..0..1
%e A232336 ..1..2..1..0..2..1..2....2..1..2..1..0..2..1....1..2..1..0..1..2..1
%Y A232336 Row 2 of A232335.
%K A232336 nonn
%O A232336 1,2
%A A232336 _R. H. Hardin_, Nov 22 2013