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%I #5 Nov 25 2018 17:30:53
%S 1,1,1,1,3,3,7,7,23,23,131,131,971,971,9431,9431,139347,139347,
%T 2886057,2886057,82544813,82544813,3341873733,3341873733,191910369845,
%U 191910369845,15522222886741,15522222886741,1764362997792863
%N Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in a 2 X 2 elbow 1,1 1,2 2,1 in any orientation.
%e Maximal 8 X 8 example:
%e 1 1 0 0 0 0 1 1
%e 1 0 1 0 0 1 0 1
%e 0 1 1 0 0 1 1 0
%e 0 0 0 0 0 0 0 0
%e 0 0 0 0 0 0 0 0
%e 0 1 1 0 0 1 1 0
%e 1 0 1 0 0 1 0 1
%e 1 1 0 0 0 0 1 1
%K nonn
%O 1,5
%A _R. H. Hardin_, Oct 25 2008
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