A178171 Number of collections of nonempty subsets of an n-element set where each element appears in at most 3 subsets.

1, 2, 8, 109, 3623, 200522, 16514461, 1912959395, 298569495981, 60701549078701, 15647889334180500, 5003666238486522124, 1948975409748003520112, 910680909359710587298621, 503845222094502583681150340, 326363222435413478204610417626, 245078255691857705139839897934085

Offset: 0

Author

Daniel E. Loeb, Dec 17 2010

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..100

Crossrefs

Row n=3 of A330964.

At most 1 subset gives Bell numbers A000110, at most 2 subsets gives A178165.

Extensions

a(7)-a(8) from Bert Dobbelaere, Sep 10 2019

Terms a(9) and beyond from Andrew Howroyd, Jan 04 2020