Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a tee 1,1 1,2 1,3 2,2 in any orientation.
A145929
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a tee 1,1 1,2 1,3 2,2 in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =8a(7) =13a(8) =44a(9) =111a(10) =556a(11) =1606a(12) =9677a(13) =40103a(14) =359014a(15) =1871694a(16) =20359902a(17) =143317291a(18) =2226693360a(19) =20614186256a(20) =404517634279
External references
- oeis: A145929