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A160448
Number of isomorphism classes of n-fold coverings of a connected graph with Betti number 6.
2
1, 1, 64, 8051, 7997683, 24883501301, 193492277719861, 3252016862827895399, 106562068594917409814646, 6292383326091360022932428280, 629238325608681213686078435061358, 101339461229675874181303485938915652000
OFFSET
0,3
COMMENTS
Number of orbits of the conjugacy action of Sym(n) on Sym(n)^6 [Kwak and Lee, 2001]. - Álvar Ibeas, Mar 24 2015
REFERENCES
J. H. Kwak and J. Lee, Enumeration of graph coverings, surface branched coverings and related group theory, in Combinatorial and Computational Mathematics (Pohang, 2000), ed. S. Hong et al., World Scientific, Singapore 2001, pp. 97-161.
LINKS
Álvar Ibeas, Table of n, a(n) for n = 0..60 [a(0)=1 prepended Georg Fischer, Apr 03 2020]
J. H. Kwak and J. Lee, Isomorphism classes of graph bundles. Can. J. Math., 42(4), 1990, pp. 747-761.
PROG
(Sage)
[sum(p.aut()**5 for p in Partitions(n)) for n in range(6)] # Álvar Ibeas, Mar 24 2015
CROSSREFS
Seventh column of A160449.
Sequence in context: A294083 A084004 A264016 * A302271 A301847 A302970
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 12 2009
EXTENSIONS
Name clarified and more terms added by Álvar Ibeas, Mar 24 2015
a(0)=1 prepended by F. Chapoton, Mar 15 2020
STATUS
approved