

A027607


Number of nonwellfounded sets or hypersets (sets that can contain themselves) of level n (representable by graphs with n nodes).


1




OFFSET

1,1


LINKS

Table of n, a(n) for n=1..7.
A. Casagrande, C. Piazza, A. Policriti, Is hyperextensionality 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



