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%I #3 Mar 31 2012 12:35:08
%S 1,1,3,13,59,335,2897,37715,690357,17737939,624778919,31083795113,
%T 2181813132547,218875670124419,30699194550031869,6100362669555259551,
%U 1691513945329277743047,667365921802550365450107
%N Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 2X2 elbow 1,1 1,2 2,1 in any orientation.
%e Maximal 8 X 8 example
%e .1.0.0.1.1.0.1.1
%e .1.1.0.0.1.0.0.1
%e .0.0.1.1.0.1.1.0
%e .1.1.0.1.0.1.0.1
%e .1.0.1.0.1.0.1.1
%e .0.1.1.0.1.1.0.0
%e .1.0.0.1.0.0.1.1
%e .1.1.0.1.1.0.0.1
%K nonn
%O 1,3
%A _R. H. Hardin_, Oct 25 2008