Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 5-point barb 1,1 1,2 2,2 2,3 3,2 in any orientation.
A146141
Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 5-point barb 1,1 1,2 2,2 2,3 3,2 in 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) =7a(11) =7a(12) =21a(13) =21a(14) =61a(15) =61a(16) =403a(17) =403a(18) =3415a(19) =3415a(20) =36395a(21) =36395a(22) =473261a(23) =473261a(24) =8291363a(25) =8291363a(26) =204964495a(27) =204964495
External references
- oeis: A146141