%I A006905 M2065
%S A006905 1,2,13,171,3994,154303,9415189,878222530,122207703623,24890747921947,
%T A006905 7307450299510288,3053521546333103057,1797003559223770324237,
%U A006905 1476062693867019126073312,1679239558149570229156802997,2628225174143857306623695576671,
               5626175867513779058707006016592954
%N A006905 Number of transitive relations on n labeled nodes.
%D A006905 D. Ford and J. McKay, personal communication, 1991.
%D A006905 Klaska (1997), Transitivity and Partial Order, Mathematica Bohemica, 
               122 (1), 75-82. Based on a correspondence between transitive relations 
               and partial orders, the author obtains a formula and calculates the 
               first 14 terms - Jeff McSweeney (jmcsween(AT)mtsu.edu), May 13, 2000
%D A006905 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A006905 S. R. Finch, <a href="http://algo.inria.fr/bsolve/">Transitive relations, 
               topologies and partial orders</a>
%H A006905 G. Pfeiffer, <a href="http://www.cs.uwaterloo.ca/journals/JIS/">Counting 
               Transitive Relations</a>, Journal of Integer Sequences, Vol. 7 (2004), 
               Article 04.3.2.
%Y A006905 Cf. A000595, A001173. See A091073 for unlabeled case.
%Y A006905 Sequence in context: A078363 A143851 A088316 this_sequence A119400 A137610 
               A073178
%Y A006905 Adjacent sequences: A006902 A006903 A006904 this_sequence A006906 A006907 
               A006908
%K A006905 nonn,nice
%O A006905 0,2
%A A006905 Simon Plouffe, N. J. A. Sloane (njas(AT)research.att.com).
%E A006905 More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 
               28 2003
%E A006905 2 more terms from Charles R. Greathouse IV Aug 30 2006