Number of n X n binary arrays symmetric under 90-degree rotation with all ones connected in a 3 X 2 elbow 1,1 1,2 1,3 2,3 in any orientation.
A145949
Number of n X n binary arrays symmetric under 90-degree rotation with all ones connected in a 3 X 2 elbow 1,1 1,2 1,3 2,3 in any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =15a(6) =35a(7) =85a(8) =321a(9) =1353a(10) =7451a(11) =43415a(12) =311247a(13) =2524635a(14) =23996463a(15) =265026943a(16) =3465054275a(17) =52737773951a(18) =953864284885
External references
- oeis: A145949