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Number of n X n binary arrays symmetric about main diagonal with all ones connected only in two by two blocks.
0

%I #3 Mar 31 2012 12:35:08

%S 1,2,3,6,16,49,169,742,3848,23784,176890,1574720,16764539,214487123,

%T 3284115855,60203667877,1323062783686,34845447884285,1099257570874298,

%U 41549582286031187,1881714538522030500,102107501292816609976

%N Number of n X n binary arrays symmetric about main diagonal with all ones connected only in two by two blocks.

%e Maximal 7 X 7 example

%e .1.1.0.0.0.1.1

%e .1.1.0.0.0.1.1

%e .0.0.1.1.0.0.0

%e .0.0.1.1.0.1.1

%e .0.0.0.0.0.1.1

%e .1.1.0.1.1.0.0

%e .1.1.0.1.1.0.0

%K nonn

%O 1,2

%A _R. H. Hardin_, Oct 22 2008