%I #5 Jul 04 2015 08:56:56
%S 20,36,190,868,4904,36522,416107,4569918,77901650,1497446190,
%T 42287505995,1268416344438,58326869184327,2894771753919566,
%U 215057618091485008,17236097050206624440,2090654209136652647325,272722696022344377007246
%N Number of (n+2)X(n+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00010101 or 01010101
%C Diagonal of A259742
%H R. H. Hardin, <a href="/A259734/b259734.txt">Table of n, a(n) for n = 1..23</a>
%e Some solutions for n=4
%e ..0..1..0..0..0..1....0..0..1..0..1..0....0..1..0..1..0..0....1..0..1..0..1..0
%e ..0..0..1..0..1..0....0..0..0..1..0..1....1..0..1..0..1..0....0..1..0..0..0..1
%e ..0..1..0..1..0..1....1..0..1..0..1..0....0..0..0..1..0..1....0..0..1..0..1..0
%e ..1..0..1..0..1..0....0..1..0..1..0..1....1..0..1..0..1..0....0..1..0..1..0..1
%e ..0..1..0..1..0..1....0..0..1..0..0..0....0..1..0..1..0..0....1..0..1..0..1..0
%e ..0..0..1..0..1..0....0..1..0..1..0..1....0..0..1..0..1..0....0..0..0..1..0..1
%Y Cf. A259742
%K nonn
%O 1,1
%A _R. H. Hardin_, Jul 04 2015
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