A030268 Number of nonisomorphic connected partial lattices.

1, 1, 1, 3, 9, 35, 153, 791, 4597, 29988, 215804, 1697291, 14457059, 132392971, 1295346365, 13468653637, 148142236784, 1716782858995, 20889118889021

Offset

0,4

Comments

A partial lattice is a poset where every pair of points has a unique least upper (greatest lower) bound or has no upper (lower) bound.

Links

Table of n, a(n) for n=0..18.

N. J. A. Sloane, Transforms

Formula

Inverse Euler transform of A006966(n-2) (lattices).

Mathematica

A006966 = Cases[Import["https://oeis.org/A006966/b006966.txt", "Table"], {_, _}][[All, 2]];
(* EulerInvTransform is defined in A022562 *)
Join[{1}, EulerInvTransform[Drop[A006966, 3]]] (* Jean-François Alcover, May 10 2019, updated Mar 17 2020 *)

Crossrefs

Sequence in context: A327885 A074507 A217924 * A097277 A034428 A338793

Adjacent sequences: A030265 A030266 A030267 * A030269 A030270 A030271

Keyword

nonn,hard

Author

Christian G. Bower, revised Dec 28 2000

Extensions

a(17) (from A006966) from Jean-François Alcover, May 10 2019

a(18) (using A006966) from Alois P. Heinz, May 10 2019

Status

approved