(A001035(n) - 1)/2 where A001035 is the number of partially ordered sets ("posets") with n labeled elements.
A105974
(A001035(n) - 1)/2 where A001035 is the number of partially ordered sets ("posets") with n labeled elements.
Terms
- a(0) =0a(1) =0a(2) =1a(3) =9a(4) =109a(5) =2115a(6) =65011a(7) =3064929a(8) =215861689a(9) =22255521255
External references
- oeis: A105974