Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1100-0111-0010 pattern in any orientation.
A146457
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1100-0111-0010 pattern in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =3a(7) =5a(8) =15a(9) =27a(10) =85a(11) =213a(12) =947a(13) =2889a(14) =18347a(15) =72469a(16) =534735a(17) =2688781a(18) =25770975a(19) =165859999a(20) =2076582639a(21) =17137608411a(22) =273236370839
External references
- oeis: A146457