Number of nonisomorphic graded posets with 0 and non-uniform Hasse graph of rank n, with exactly 2 elements of each rank above 0.

A206947

Number of nonisomorphic graded posets with 0 and non-uniform Hasse graph of rank n, with exactly 2 elements of each rank above 0.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =2a(4) =14a(5) =70a(6) =306a(7) =1248a(8) =4888a(9) =18666a(10) =70110a(11) =260414a(12) =959882a(13) =3519232a(14) =12854064a(15) =46824210a(16) =170243566a(17) =618125238a(18) =2242100898a(19) =8126927456a(20) =29442587720a(21) =106626616954a(22) =386046638142

External references