Number of n X n binary arrays symmetric about the diagonal and 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.

A145948

Number of n X n binary arrays symmetric about the diagonal and 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) =1a(5) =1a(6) =1a(7) =1a(8) =3a(9) =3a(10) =13a(11) =13a(12) =41a(13) =41a(14) =227a(15) =227a(16) =1869a(17) =1869a(18) =21295a(19) =21295a(20) =308993a(21) =308993a(22) =6084845a(23) =6084845a(24) =167200773a(25) =167200773a(26) =6380227531a(27) =6380227531a(28) =331792369009a(29) =331792369009

External references