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A027607 Number of non-well-founded sets or hypersets (sets that can contain themselves) of level n (representable by graphs with n nodes). 1

%I #20 Apr 29 2016 17:28:31

%S 2,2,16,504,52944,17294924,17347940328

%N Number of non-well-founded sets or hypersets (sets that can contain themselves) of level n (representable by graphs with n nodes).

%H A. Casagrande, C. Piazza, A. Policriti, <a href="http://sets2015.cnam.fr/papers/00010001.pdf">Is hyper-extensionality preservable under deletions of graph elements?</a>, Preprint 2015.

%H Christopher Tubbs et al., <a href="https://github.com/ctubbsii/hypersets">GitHub Hypersets Project</a> for generating integers in the sequence.

%K nonn,hard,more

%O 1,1

%A Elaine Milito (emilito(AT)bird.wcupa.edu)

%E a(6)-a(7) from _Christopher Tubbs_, Oct 19 2013

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Last modified February 28 20:40 EST 2024. Contains 370400 sequences. (Running on oeis4.)