Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in a zee 1,1 1,2 2,2 2,3 in any orientation.
A145957
Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in a zee 1,1 1,2 2,2 2,3 in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =3a(9) =3a(10) =9a(11) =9a(12) =23a(13) =23a(14) =125a(15) =125a(16) =821a(17) =821a(18) =6239a(19) =6239a(20) =71403a(21) =71403a(22) =1048093a(23) =1048093a(24) =19913069a(25) =19913069a(26) =517074745a(27) =517074745a(28) =17642361171a(29) =17642361171
External references
- oeis: A145957