A146142 - OEIS

A146142

Number of n X n binary arrays symmetric 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 1,1,1,1,1,3,23,43,81,319,1397,6447,41775,230237,1798489,13587111,

%T 143546329,1450499749,20575847369,276390467445,5233548027451,

%U 93375391444657

%N Number of n X n binary arrays symmetric 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 8 X 8 example

%e .0.0.0.0.1.0.0.0

%e .0.0.0.0.1.1.0.0

%e .0.1.0.1.1.0.0.0

%e .1.1.1.0.0.1.0.0

%e .0.0.1.0.0.1.1.1

%e .0.0.0.1.1.0.1.0

%e .0.0.1.1.0.0.0.0

%e .0.0.0.1.0.0.0.0

%K nonn

%O 1,6

%A _R. H. Hardin_, Oct 27 2008