A146040 - OEIS

A146040

Number of n X n binary arrays symmetric under horizontal and vertical reflection with all 1's connected only in a 2 X 4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation.

%I #5 May 24 2021 15:00:29

%S 1,1,1,1,1,1,1,1,29,29,249,249,4021,4021,99935,99935,4398251,4398251,

%T 362789159,362789159,47338031953,47338031953,10727733486159,

%U 10727733486159

%N Number of n X n binary arrays symmetric under horizontal and vertical reflection with all 1's connected only in a 2 X 4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation.

%e Maximal 9 X 9 example

%e .1.0.0.1.0.1.0.0.1

%e .1.1.0.1.0.1.0.1.1

%e .1.0.1.1.0.1.1.0.1

%e .1.0.0.1.0.1.0.0.1

%e .0.0.0.0.0.0.0.0.0

%e .1.0.0.1.0.1.0.0.1

%e .1.0.1.1.0.1.1.0.1

%e .1.1.0.1.0.1.0.1.1

%e .1.0.0.1.0.1.0.0.1

%K nonn

%O 1,9

%A _R. H. Hardin_, Oct 26 2008