Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 2X2 elbow 1,1 1,2 2,1 in any orientation.
A145937
Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 2X2 elbow 1,1 1,2 2,1 in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =5a(5) =5a(6) =19a(7) =19a(8) =161a(9) =161a(10) =4227a(11) =4227a(12) =156459a(13) =156459a(14) =12465353a(15) =12465353a(16) =2072728127a(17) =2072728127a(18) =654619864141a(19) =654619864141
External references
- oeis: A145937