Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in a 2 X 4 el 1,1 1,2 1,3 1,4 2,4 with any orientation.
A146020
Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in a 2 X 4 el 1,1 1,2 1,3 1,4 2,4 with any orientation.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =1a(9) =1a(10) =3a(11) =3a(12) =13a(13) =13a(14) =41a(15) =41a(16) =219a(17) =219a(18) =1033a(19) =1033a(20) =8217a(21) =8217a(22) =92671a(23) =92671a(24) =1241193a(25) =1241193a(26) =21102313
External references
- oeis: A146020