A049292 - OEIS

A049292

Number of subgroups of index n in fundamental group of a closed surface of characteristic -3.

1, 31, 1330, 119315, 17543016, 4537258768

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OFFSET

1,2

COMMENTS

A formula in terms of irreducible characters of the symmetric group.

REFERENCES

V. A. Liskovets and A. Mednykh, Enumeration of subgroups in the fundamental groups of orientable circle bundles over surfaces, Commun. in Algebra, 28, No. 4 (2000), 1717-1738.

A. D. Mednykh, On the number of subgroups in the fundamental group of a closed surface. Commun. in Algebra, 16, No 10 (1988), 2137-2148.

LINKS

Table of n, a(n) for n=1..6.

CROSSREFS

Cf. A003319, A027837, A049290-A049295.

Sequence in context: A139162 A078961 A261856 * A289473 A069406 A234115

Adjacent sequences: A049289 A049290 A049291 * A049293 A049294 A049295

KEYWORD

nonn,nice

AUTHOR

Valery A. Liskovets

STATUS

approved