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URL: https://oeis.org/A362172

⇱ A362172 - OEIS


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A362172
a(n) = the hypergraph Catalan number C_7(n).
11
1, 1, 3432, 141858288, 40309820014464, 53321581727982247680, 238681094467043912358445056, 2924960829706245011243295851200512, 84750120431280677998861681616641721991168, 5208807724759446156144077076658272647436908396544
OFFSET
0,3
COMMENTS
Let m >= 1. The sequence of hypergraph Catalan numbers {C_m(n): n >= 0} is defined in terms of counting walks on trees, weighted by the orders of their automorphism groups. See Gunnells. When m = 1 we get the sequence of Catalan numbers A000108. The present sequence is the case m = 7.
Gunnells gives several combinatorial interpretations of the hypergraph Catalan numbers, a method to compute their generating functions to arbitrary precision and some conjectural asymptotics.
LINKS
Paul E. Gunnells, Generalized Catalan numbers from hypergraphs, arXiv:2102.05121 [math.CO], 2021.
FORMULA
a(n) ~ sqrt(7)/4 * (7^6/6!)^n * n!^6/(Pi*n)^3 (conjectural).
CROSSREFS
KEYWORD
nonn,walk
AUTHOR
Peter Bala, Apr 10 2023
EXTENSIONS
a(7) onwards from Andrew Howroyd, Feb 01 2024
STATUS
approved