Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 2X2 block with tail 1,1 1,2 1,3 2,2 2,3 in any orientation.
A146052
Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 2X2 block with tail 1,1 1,2 1,3 2,2 2,3 in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =13a(6) =33a(7) =59a(8) =183a(9) =775a(10) =3549a(11) =21203a(12) =124205a(13) =885931a(14) =6938155a(15) =65072235a(16) =697161911a(17) =8870657391a(18) =129325569203
External references
- oeis: A146052