Number of ways to place two non-attacking queens on all free n-ominoes.
A171009
Number of ways to place two non-attacking queens on all free n-ominoes.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =2a(4) =21a(5) =131a(6) =733a(7) =3882a(8) =19641a(9) =97282
External references
- oeis: A171009