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Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1101-0111 pattern in any orientation.
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%I #4 Mar 31 2012 12:35:12

%S 1,1,1,1,1,1,3,7,15,27,51,141,615,2523,10593,40853,196793,1114237,

%T 8094209,59485011,492771709,4132732207,42832582765,478558556527

%N Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1101-0111 pattern in any orientation.

%e Maximal 8 X 8 example

%e .0.1.1.0.1.0.0.0

%e .1.0.1.1.1.0.0.0

%e .1.1.0.0.0.0.0.0

%e .0.1.0.0.0.0.1.1

%e .1.1.0.0.0.0.1.0

%e .0.0.0.0.0.0.1.1

%e .0.0.0.1.1.1.0.1

%e .0.0.0.1.0.1.1.0

%K nonn

%O 1,7

%A _R. H. Hardin_, Nov 04 2008