%I A028857
%S A028857 2,6,18,94,500,3485
%N A028857 Number of prime unlabeled connected topologies (i.e. prime connected 
               homeomorphism classes) on n points.
%D A028857 R. Kreminski, "Graphs and matrices in the study of (finite) topological 
               spaces", Missouri J. Mathematical Sciences, Volume 12 (Issue #2, 
               Spring 2000).
%H A028857 <a href="http://www.math-cs.ucmo.edu/~mjms/mjms.html">Missouri J. Mathematical 
               Sciences</a> (New web address)
%Y A028857 Sequence in context: A165774 A053505 A000138 this_sequence A052687 A162059 
               A162060
%Y A028857 Adjacent sequences: A028854 A028855 A028856 this_sequence A028858 A028859 
               A028860
%K A028857 nonn
%O A028857 2,1
%A A028857 Richard M Kreminski (kremin(AT)boisdarc.tamu-commerce.edu)