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Number of transitive relations on n unlabeled points.
4

%I #13 Mar 18 2017 16:13:46

%S 1,2,8,39,242,1895,19051,246895,4145108,90325655,2555630036,

%T 93810648902,4461086120602,274339212258846,21775814889230580,

%U 2226876304576948549

%N Number of transitive relations on n unlabeled points.

%C a(13)-a(15) are from Brinkmann's and McKay's paper. - _Vladeta Jovovic_, Jan 07 2006

%H Gunnar Brinkmann and Brendan D. McKay, <a href="http://users.cecs.anu.edu.au/~bdm/papers/topologies.pdf">Counting unlabelled topologies and transitive relations</a>.

%H Gunnar Brinkmann and Brendan D. McKay, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL8/McKay/mckay170.html">Counting Unlabelled Topologies and Transitive Relations</a>, Journal of Integer Sequences, Vol. 8 (2005), Article 05.2.1.

%H G. Pfeiffer, <a href="http://schmidt.nuigalway.ie/~goetz/pub/posetseq.html">Counting Transitive Relations</a>, preprint, 2004.

%H G. Pfeiffer, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL7/Pfeiffer/pfeiffer6.html">Counting Transitive Relations</a>, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.2.

%Y Cf. A079265 (antisymmetric transitive relations), A001930 (reflexive transitive relations), A000112 (partial orders), A006905 (labeled transitive relations).

%K hard,nonn,nice

%O 0,2

%A Goetz Pfeiffer (goetz.pfeiffer(AT)nuigalway.ie), Jan 21 2004

%E More terms from _Vladeta Jovovic_, Jan 07 2006