Number of n X n binary arrays symmetric 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.
A146142
Number of n X n binary arrays symmetric 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) =3a(6) =23a(7) =43a(8) =81a(9) =319a(10) =1397a(11) =6447a(12) =41775a(13) =230237a(14) =1798489a(15) =13587111a(16) =143546329a(17) =1450499749a(18) =20575847369a(19) =276390467445
External references
- oeis: A146142