Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected in a 3X2 elbow 1,1 1,2 1,3 2,3 in any orientation.
A145947
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected in a 3X2 elbow 1,1 1,2 1,3 2,3 in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =3a(6) =9a(7) =19a(8) =41a(9) =145a(10) =647a(11) =3181a(12) =16339a(13) =99371a(14) =747763a(15) =6609081a(16) =67311501a(17) =786968963a(18) =10964146353a(19) =178363016765
External references
- oeis: A145947