Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in a 3 X 3 "plus" shape (e.g., consisting of the points at the coordinates (2,1), (2,2), (2,3), (1,2), (3,2)).
A146002
Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected only in a 3 X 3 "plus" shape (e.g., consisting of the points at the coordinates (2,1), (2,2), (2,3), (1,2), (3,2)).
Terms
- a(0) =1a(1) =1a(2) =2a(3) =1a(4) =2a(5) =1a(6) =5a(7) =2a(8) =9a(9) =3a(10) =28a(11) =6a(12) =76a(13) =13a(14) =295a(15) =41a(16) =1196a(17) =134a(18) =6337a(19) =523a(20) =36933a(21) =2341a(22) =266568a(23) =13112a(24) =2186885a(25) =85330a(26) =21909179a(27) =657274a(28) =253725200a(29) =5867785
External references
- oeis: A146002