|
%I #5 Aug 03 2019 08:43:41
%S 1,2,5,14,47,186,904,5439,41418,404501,5122188,84623842,1828876351,
%T 51701216248,1908493827243,91755916071736,5729050033597431
%N Number of unlabeled topologies with up to n points.
%e Non-isomorphic representatives of the a(0) = 1 through a(3) = 14 topologies:
%e {} {} {} {}
%e {}{1} {}{1} {}{1}
%e {}{12} {}{12}
%e {}{2}{12} {}{123}
%e {}{1}{2}{12} {}{2}{12}
%e {}{3}{123}
%e {}{23}{123}
%e {}{1}{2}{12}
%e {}{1}{23}{123}
%e {}{3}{23}{123}
%e {}{2}{3}{23}{123}
%e {}{3}{13}{23}{123}
%e {}{2}{3}{13}{23}{123}
%e {}{1}{2}{3}{12}{13}{23}{123}
%Y Partial sums of A001930.
%Y The labeled version is A326878.
%Y Cf. A000612, A000798, A003180, A108800, A193675, A306445, A326867, A326882.
%K nonn
%O 0,2
%A _Gus Wiseman_, Aug 02 2019
|
