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Search: id:A057006
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| A057006 |
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Number of conjugacy classes of subgroups of index n in free group of rank 3. |
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+0
2
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| 1, 7, 41, 604, 13753, 504243, 24824785, 1598346352, 129958211233, 13030565312011, 1579721338432537, 227804599861102676, 38541084552054952009, 7560534755192908672087, 1702288146755359962223409
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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J. H. Kwak and J. Lee, J. Graph Th., 23 (1996), 105-109.
V. A. Liskovets, Reductive enumeration under mutually orthogonal group actions, Acta Applic. Math., 52 (1998), 91-120.
R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 5.13(c), pp. 76, 112.
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LINKS
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J. H. Kwak and J. Lee, Enumeration of graph coverings and surface branched coverings, Lecture Note Series 1 (2001), Com^2MaC-KOSEF, Korea. See chapter 3.
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CROSSREFS
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Cf. A057004-A057013.
Sequence in context: A125120 A053676 A002701 this_sequence A102532 A044109 A110451
Adjacent sequences: A057003 A057004 A057005 this_sequence A057007 A057008 A057009
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KEYWORD
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nonn
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AUTHOR
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njas, Sep 09 2000
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EXTENSIONS
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More terms from Francisco Salinas (franciscodesalinas(AT)hotmail.com), Dec 25 2001
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