Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 5-point zee 1,1 2,1 2,2 2,3 3,3 in any orientation.
A146067
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 5-point zee 1,1 2,1 2,2 2,3 3,3 in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =5a(8) =9a(9) =17a(10) =41a(11) =117a(12) =275a(13) =1237a(14) =4103a(15) =20885a(16) =85925a(17) =519635a(18) =2644535a(19) =20312399a(20) =128516271a(21) =1266040749a(22) =10025925703a(23) =122157386121
External references
- oeis: A146067