A022017 - OEIS

A022017

Number of connected partially ordered sets with n "lines": pairs (a,b) where a < b and there is no c with a < c < b. The lines form the minimal basis for the partial ordering.

%I #33 Sep 10 2024 08:04:48

%S 1,3,8,29,103,442,1953,9502,48533,262634

%N Number of connected partially ordered sets with n "lines": pairs (a,b) where a < b and there is no c with a < c < b. The lines form the minimal basis for the partial ordering.

%C The points are unlabeled.

%D See A000112 for references and links about partially ordered sets.

%H N. J. A. Sloane, <a href="/A022016/a022016.jpg">Illustration of initial terms of A022016 and A022017.</a>

%H <a href="/index/Pos#posets">Index entries for sequences related to posets</a>

%e See Sloane's link.

%Y Cf. A000112, A000608, A022016. Column sums of A342590.

%K nonn,more

%O 1,2

%A _Franklin T. Adams-Watters_, Mar 30 2002

%E a(6) to a(9) from A342590. - _R. J. Mathar_, Mar 21 2021

%E a(10) from Rico Zöllner and _Konrad Handrich_, Sep 10 2024