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A319540 Number of unlabeled 3-uniform hypergraphs spanning n vertices such that every pair of vertices appears together in some block. 4
1, 1, 0, 1, 2, 14, 964, 3908438 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..7.

EXAMPLE

Non-isomorphic representatives of the a(5) = 14 hypergraphs:

              {{123}{145}{245}{345}}

            {{123}{124}{135}{245}{345}}

            {{123}{145}{235}{245}{345}}

          {{123}{134}{145}{235}{245}{345}}

          {{123}{145}{234}{235}{245}{345}}

          {{124}{135}{145}{235}{245}{345}}

          {{125}{135}{145}{235}{245}{345}}

        {{123}{124}{135}{145}{235}{245}{345}}

        {{124}{135}{145}{234}{235}{245}{345}}

        {{125}{135}{145}{234}{235}{245}{345}}

      {{123}{124}{135}{145}{234}{235}{245}{345}}

      {{125}{134}{135}{145}{234}{235}{245}{345}}

    {{124}{125}{134}{135}{145}{234}{235}{245}{345}}

  {{123}{124}{125}{134}{135}{145}{234}{235}{245}{345}}

CROSSREFS

The labeled case is A302394.

Cf. A000665, A006126, A006129, A038041, A299471, A301922, A302374, A306021, A320395, A322451.

Sequence in context: A144017 A032419 A225163 * A190634 A130421 A227403

Adjacent sequences:  A319537 A319538 A319539 * A319541 A319542 A319543

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, Jan 09 2019

EXTENSIONS

a(6)-a(7) from Andrew Howroyd, Aug 17 2019

STATUS

approved

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Last modified September 29 21:59 EDT 2020. Contains 337432 sequences. (Running on oeis4.)