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A178171 Number of collections of nonempty subsets of an n-element set where each element appears in at most 3 subsets. 4
1, 2, 8, 109, 3623, 200522, 16514461, 1912959395, 298569495981, 60701549078701, 15647889334180500, 5003666238486522124, 1948975409748003520112, 910680909359710587298621, 503845222094502583681150340, 326363222435413478204610417626, 245078255691857705139839897934085 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

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.

Sequence in context: A008926 A136468 A322643 * A132523 A012554 A012665

Adjacent sequences:  A178168 A178169 A178170 * A178172 A178173 A178174

KEYWORD

nonn

AUTHOR

Daniel E. Loeb, Dec 17 2010

EXTENSIONS

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

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

STATUS

approved

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Last modified January 22 22:16 EST 2020. Contains 331166 sequences. (Running on oeis4.)