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%I #8 Dec 30 2018 06:35:15
%S 28,33,63,97,183,289,547,865,1639,2593,4915,7777,14743,23329,44227,
%T 69985,132679,209953,398035,629857,1194103,1889569,3582307,5668705,
%U 10746919,17006113,32240755,51018337,96722263,153055009,290166787,459165025
%N Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010001 00010101 or 01010101.
%H R. H. Hardin, <a href="/A261106/b261106.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) + 3*a(n-2) - 3*a(n-3) for n>6.
%F Empirical g.f.: x*(28 + 5*x - 54*x^2 + 19*x^3 - 4*x^4 + 4*x^5) / ((1 - x)*(1 - 3*x^2)). - _Colin Barker_, Dec 30 2018
%e Some solutions for n=4:
%e ..0..1..0....1..0..0....1..0..0....0..0..0....0..1..0....1..0..0....0..1..0
%e ..0..0..1....0..0..0....0..1..0....1..0..1....0..1..0....0..1..0....1..0..1
%e ..0..1..0....1..0..1....1..0..1....0..1..0....0..1..0....0..0..1....0..1..0
%e ..1..0..1....0..0..0....0..0..0....1..0..1....0..1..0....0..1..0....1..0..0
%e ..0..0..0....1..0..1....1..0..1....0..1..0....0..1..0....1..0..1....0..1..0
%e ..1..0..0....0..1..0....0..0..0....0..0..1....0..1..0....0..1..0....0..0..1
%Y Column 1 of A261113.
%K nonn
%O 1,1
%A _R. H. Hardin_, Aug 08 2015
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