Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1000-1111-1000 pattern in any orientation.
A147127
Number of n X n binary arrays symmetric about both diagonal and antidiagonal 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) =3a(9) =7a(10) =15a(11) =27a(12) =51a(13) =137a(14) =397a(15) =1327a(16) =4515a(17) =15837a(18) =61007a(19) =262125a(20) =1291801
External references
- oeis: A147127