A160447 Number of isomorphism classes of n-fold coverings of a connected graph with Betti number 5.

1, 1, 32, 1393, 336465, 207388305, 268749463729, 645244638648481, 2642912633259448386, 17340131659334061379490, 173401255467914281827442642, 2538767439061885080225425717858, 52643878634689290630033137748571475

Offset

0,3

Comments

Number of orbits of the conjugacy action of Sym(n) on Sym(n)^5 [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 by 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()**4 for p in Partitions(n)) for n in range(6)] # Álvar Ibeas, Mar 24 2015

Crossrefs

Sixth column of A160449.

Sequence in context: A241800 A231040 A254152 * A302263 A302963 A302806

Adjacent sequences: A160444 A160445 A160446 * A160448 A160449 A160450

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