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%I #6 May 09 2023 06:27:05
%S 2,3,4,7,11,18,30,49,81,134,221,365,603,996,1645,2717,4488,7413,12244,
%T 20224,33405,55176,91136,150533,248641,410689,678350,1120456,1850698,
%U 3056865,5049136,8339843,13775223,22753039,37582027,62075608,102532550
%N Number of nX2 0..1 arrays with every element unequal to 0, 1 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
%C Column 2 of A317773.
%H R. H. Hardin, <a href="/A317767/b317767.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) +2*a(n-3) -a(n-6)
%F Empirical: G.f.: -x*(x-1)*(x^4+3*x^3+4*x^2+3*x+2)/(1-x-2*x^3+x^6) . - _R. J. Mathar_, May 09 2023
%e Some solutions for n=5
%e ..0..0. .0..1. .0..0. .0..0. .0..0. .0..0. .0..1. .0..0. .0..0. .0..1
%e ..0..0. .0..0. .1..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..1. .0..0
%e ..0..0. .0..0. .1..1. .0..0. .0..0. .0..1. .0..0. .1..0. .0..1. .0..0
%e ..0..0. .0..0. .1..1. .0..0. .1..0. .0..1. .0..0. .1..1. .1..1. .1..0
%e ..0..0. .1..0. .1..1. .1..0. .1..1. .1..1. .0..0. .1..1. .1..1. .1..1
%Y Cf. A317773.
%K nonn
%O 1,1
%A _R. H. Hardin_, Aug 06 2018
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