%I #8 May 11 2018 20:11:43
%S 3,9,14,29,67,134,275,583,1210,2511,5245,10926,22745,47405,98774,
%T 205765,428731,893294,1861163,3877815,8079642,16834247,35074949,
%U 73080470,152266769,317255517,661018310,1377265789,2869604691,5978971062
%N Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,0,1,1,1 for x=0,1,2,3,4.
%C Every 0 is next to 0 2's, every 1 is next to 1 0's, every 2 is next to 2 1's, every 3 is next to 3 1's, every 4 is next to 4 1's.
%C Column 2 of A197280.
%H R. H. Hardin, <a href="/A197274/b197274.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = 2*a(n-1) +2*a(n-3) -2*a(n-4) -2*a(n-5) -a(n-6) -2*a(n-7).
%F Empirical g.f.: (1 + x)^2*(3 - 3*x - x^2 - 2*x^4) / (1 - 2*x - 2*x^3 + 2*x^4 + 2*x^5 + x^6 + 2*x^7). - _Colin Barker_, May 11 2018
%e Some solutions for n=4:
%e ..2..1....0..0....0..1....0..1....2..1....0..0....2..1....1..0....1..0....0..1
%e ..1..0....0..0....1..1....0..1....1..0....1..1....1..0....3..1....1..0....1..3
%e ..1..0....0..0....1..0....0..1....1..0....1..1....1..1....1..1....1..0....1..1
%e ..2..1....0..0....2..1....1..2....1..0....0..0....0..1....0..0....1..0....0..0
%Y Cf. A197280.
%K nonn
%O 1,1
%A _R. H. Hardin_, Oct 12 2011
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