A146148 - OEIS

A146148

Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in an em 1,1 1,2 2,2 2,3 3,3 in any orientation.

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

%S 1,1,1,3,5,7,25,61,137,491,1895,6799,35271,188161,1045823,6942831,

%T 54475785,429190219,4220050567,45840848045,555820995851,7424820570827,

%U 118936859724455,2001479983540325,39919686781316217,873987056828886899

%N Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in an em 1,1 1,2 2,2 2,3 3,3 in any orientation.

%e Maximal 8 X 8 example

%e .0.0.1.0.0.1.1.0

%e .0.1.1.0.0.0.1.1

%e .1.1.0.1.1.0.0.1

%e .0.0.1.0.1.1.0.0

%e .0.0.1.1.0.1.0.0

%e .1.0.0.1.1.0.1.1

%e .1.1.0.0.0.1.1.0

%e .0.1.1.0.0.1.0.0

%K nonn

%O 1,4

%A _R. H. Hardin_, Oct 27 2008