Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 1000-1000-1111-1000 pattern in any orientation.
A147125
Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 1000-1000-1111-1000 pattern in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =9a(9) =9a(10) =33a(11) =33a(12) =105a(13) =105a(14) =641a(15) =641a(16) =8787a(17) =8787a(18) =211111a(19) =211111a(20) =4653287
External references
- oeis: A147125