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Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 5-point barb 1,1 1,2 2,2 2,3 3,2 in any orientation.
0

%I #3 Mar 31 2012 12:35:09

%S 1,1,1,1,13,51,327,1743,13905,216443,3286293,80038799,2242888197,

%T 93345565591,4572631279405,334861611729305

%N Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 5-point barb 1,1 1,2 2,2 2,3 3,2 in any orientation.

%e Maximal 8 X 8 example

%e .0.1.1.0.0.0.1.0

%e .1.1.0.0.0.1.1.1

%e .0.1.0.0.1.0.0.1

%e .0.0.1.0.1.1.1.0

%e .0.1.1.1.0.1.0.0

%e .1.0.0.1.0.0.1.0

%e .1.1.1.0.0.0.1.1

%e .0.1.0.0.0.1.1.0

%K nonn

%O 1,5

%A _R. H. Hardin_, Oct 27 2008