0,3

a(13)-a(16) from Brinkmann's and McKay's paper, sent by Vladeta Jovovic (vladeta(AT)Eunet.yu), Jan 04 2006

Gunnar Brinkmann and Brendan D. McKay, Counting Unlabeled Topologies and Transitive Relations, Journal of Integer Sequences, Vol. 8 (2005), Article 05.2.1.

K. K.-H. Butler and G. Markowsky, Enumeration of finite topologies, Proc. 4th S-E Conf. Combin., Graph Theory, Computing, Congress. Numer. 8 (1973), 169-184.

F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 218 (but the last entry is wrong).

J. A. Wright, There are 718 6-point topologies, quasi-orderings, and transgraphs, Notices Amer. Math. Soc., 17 (1970), p. 646, Abstract #70T-A106.

J. A. Wright, personal communication.

For further references concerning the enumeration of topologies and posets see under A000112 and A001035.

Moussa Benoumhani, The Number of Topologies on a Finite Set, Journal of Integer Sequences, Vol. 9 (2006), Article 06.2.6.

Gunnar Brinkmann and Brendan D. McKay, Counting unlabeled topologies and transitive relations.

P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5.

S. R. Finch, Transitive relations, topologies and partial orders

G. Pfeiffer, Counting Transitive Relations, preprint, 2004.

G. Pfeiffer, Counting Transitive Relations, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.2.

D. Rusin, More info and references

N. J. A. Sloane, Classic Sequences

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Cf. A000798 (labeled topologies), A001035 (labeled posets), A001930 (unlabeled topologies), A000112 (unlabeled posets), A006057, A001928, A001929.

Adjacent sequences: A001927 A001928 A001929 this_sequence A001931 A001932 A001933

Sequence in context: A084508 A098742 A009212 this_sequence A049425 A012584 A101899

nonn,hard,nice

njas

a(8)-a(12) from Goetz Pfeiffer (goetz.pfeiffer(AT)nuigalway.ie), Jan 21 2004