A146140 - OEIS

A146140

Number of n X n binary arrays symmetric about both diagonal and antidiagonal 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 1,1,1,1,1,1,5,13,25,57,197,913,4565,21033,117411,799889,6782571,

%T 62778947,652383615,7631737235,109519353841,1777185991253,

%U 33840206146839,713322877970345,17898267949061373,507994433535644661

%N Number of n X n binary arrays symmetric about both diagonal and antidiagonal 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 .0.0.0.1.1.0.1.0

%e .0.0.1.0.0.1.1.1

%e .1.1.1.0.0.1.0.0

%e .0.1.0.1.1.0.0.0

%e .0.0.1.1.0.0.0.0

%e .0.0.0.1.0.0.0.0

%K nonn

%O 1,7

%A _R. H. Hardin_, Oct 27 2008