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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
2, 2, 16, 504, 52944, 17294924, 17347940328 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..7.

A. Casagrande, C. Piazza, A. Policriti, Is hyper-extensionality preservable under deletions of graph elements?, Preprint 2015.

Christopher Tubbs et al., GitHub Hypersets Project for generating integers in the sequence.

CROSSREFS

Sequence in context: A012520 A012323 A009804 * A100680 A002567 A238289

Adjacent sequences:  A027604 A027605 A027606 * A027608 A027609 A027610

KEYWORD

nonn,hard,more

AUTHOR

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

EXTENSIONS

a(6)-a(7) from Christopher Tubbs, Oct 19 2013

STATUS

approved

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Last modified February 19 01:03 EST 2020. Contains 332028 sequences. (Running on oeis4.)