A146141 - OEIS

A146141

Number of n X n binary arrays symmetric about the diagonal and under 90 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.

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

%S 1,1,1,1,1,1,1,1,1,1,7,7,21,21,61,61,403,403,3415,3415,36395,36395,

%T 473261,473261,8291363,8291363,204964495,204964495

%N Number of n X n binary arrays symmetric about the diagonal and under 90 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 11 X 11 example

%e .0.0.0.1.0.0.0.1.0.0.0

%e .0.0.1.1.0.0.0.1.1.0.0

%e .0.1.0.1.1.0.1.1.0.1.0

%e .1.1.1.0.0.0.0.0.1.1.1

%e .0.0.1.0.0.0.0.0.1.0.0

%e .0.0.0.0.0.0.0.0.0.0.0

%e .0.0.1.0.0.0.0.0.1.0.0

%e .1.1.1.0.0.0.0.0.1.1.1

%e .0.1.0.1.1.0.1.1.0.1.0

%e .0.0.1.1.0.0.0.1.1.0.0

%e .0.0.0.1.0.0.0.1.0.0.0

%K nonn

%O 1,11

%A _R. H. Hardin_, Oct 27 2008