Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1101-0111-0001 pattern in any orientation.
A147235
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1101-0111-0001 pattern in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =3a(8) =7a(9) =15a(10) =31a(11) =65a(12) =185a(13) =517a(14) =1673a(15) =6585a(16) =26113a(17) =126591a(18) =608081a(19) =3381041a(20) =20245821a(21) =136182387
External references
- oeis: A147235