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%I #42 Mar 04 2024 08:48:10
%S 1,1,4,12,47,174,749,3291,15675
%N Number of partially ordered sets with no isolated points and 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.
%C Lower bounds via A342447 are a(6) >= 745, a(7) >= 3212. - _R. J. Mathar_, Mar 16 2021
%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>.
%e See Sloane's link.
%Y Cf. A000112, A022017, A342447.
%K nonn,more
%O 0,3
%A _Franklin T. Adams-Watters_, Mar 30 2002
%E a(6) from _Konrad Handrich_, Dec 01 2023
%E a(7) from Rico Zöllner and _Konrad Handrich_, Feb 22 2024
%E a(8) from Rico Zöllner and _Konrad Handrich_, Mar 04 2024
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