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A137814 Smallest size (greater than 1) of a topology that cannot be made using n points. 1

%I

%S 3,5,7,11,19,29,47,79,127,191

%N Smallest size (greater than 1) of a topology that cannot be made using n points.

%D K. Ragnarsson and B. E. Tenner, Obtainable sizes of topologies on finite sets, J. Combin. Theory Ser. A 117 (2010) 138-151.

%e There is no topology on 3 points having 7 open sets. However, there do exist topologies on 3 points that have 2, 3, 4, 5 and 6 open sets.

%Y Cf. A137813.

%K nonn

%O 1,1

%A _Bridget Tenner_, Feb 11 2008

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Last modified July 30 13:12 EDT 2014. Contains 245069 sequences.