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%I #6 Mar 31 2012 12:35:46
%S 1,3,11,34,111,361,1172,3809,12377,40218,130687,424661,1379916,
%T 4483973,14570461,47346034,153848731,499924281,1624480652,5278674169,
%U 17152805697,55737242698,181115572487,588526611821,1912389796556,6214221516093
%N Half the number of nX2 binary arrays with each element equal to at least one neighbor
%C Column 2 of A180771
%H R. H. Hardin, <a href="/A180762/b180762.txt">Table of n, a(n) for n=1..99</a>
%F Empirical: a(n) = 3*a(n-1) + a(n-2) - 2*a(n-4).
%F Empirical G.f.: x*(1-x)*(1+x+2*x^2)/(1-3*x-x^2+2*x^4). [Colin Barker, Feb 22 2012]
%K nonn
%O 1,2
%A _R. H. Hardin_ Sep 20 2010
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