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Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation.
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%I #3 Mar 31 2012 12:35:08

%S 1,1,1,3,7,19,89,399,1939,11793,102715,985113,13989079,211198639,

%T 4331591655,98297746517,2965968725989,100683520176799

%N Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation.

%e Maximal 8 X 8 example

%e .0.0.0.0.0.1.1.1

%e .1.1.1.0.0.0.0.1

%e .1.0.0.1.1.1.0.1

%e .1.0.1.0.0.1.0.0

%e .0.0.1.0.0.1.0.1

%e .1.0.1.1.1.0.0.1

%e .1.0.0.0.0.1.1.1

%e .1.1.1.0.0.0.0.0

%K nonn

%O 1,4

%A _R. H. Hardin_, Oct 26 2008