Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 2X2 block with tail 1,1 1,2 1,3 2,2 2,3 in any orientation.
A146048
Number of n X n binary arrays symmetric under horizontal and vertical reflection 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) =1a(6) =17a(7) =17a(8) =57a(9) =57a(10) =781a(11) =781a(12) =24351a(13) =24351a(14) =931801a(15) =931801a(16) =62200649a(17) =62200649a(18) =8963823755a(19) =8963823755
External references
- oeis: A146048