A145971 - OEIS

A145971

Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a one by five or five by one block.

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

%S 1,1,1,1,9,9,54,93,747,1903,18738,80363,1083847,6706491,120203159,

%T 1028058854

%N Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a one by five or five by one block.

%e Maximal 8 X 8 example

%e .1.1.1.1.1.0.0.1

%e .0.0.0.0.0.0.0.1

%e .0.1.1.1.1.1.0.1

%e .1.0.0.0.0.0.0.1

%e .1.0.1.1.1.1.1.0

%e .1.0.0.0.0.0.0.0

%e .1.0.0.1.1.1.1.1

%K nonn

%O 1,5

%A _R. H. Hardin_, Oct 25 2008