cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A005432 Number of permutation groups of degree n (or, number of distinct subgroups of symmetric group S_n, counting conjugates as distinct).

Original entry on oeis.org

1, 1, 2, 6, 30, 156, 1455, 11300, 151221, 1694723, 29594446, 404126228, 10594925360, 175238308453, 5651774693595, 117053117995400, 5320744503742316, 125889331236297288, 7598016157515302757
Offset: 0

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Author

Keywords

Comments

Labeled version of A000638.
L. Pyber shows c^(n^2(1+o(1))) <= a(n) <= d^(n^2(1+o(1))), c=2^(1/16), d=24^(1/6); conjectures lower bound is accurate.

References

  • C. C. Sims, Computational methods in the study of permutation groups, pp. 169-183 of J. Leech, editor, Computational Problems in Abstract Algebra. Pergamon, Oxford, 1970.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • GAP
    List([2..5],n->Sum( List( ConjugacyClassesSubgroups( SymmetricGroup(n)), Size))); [Alexander Hulpke]
  • Magma
    n := 5; &+[ Length(s):s in SubgroupLattice(Sym(n)) ];
    

Formula

Exponential transform of A116655. Binomial transform of A116693. - Christian G. Bower, Feb 23 2006

Extensions

a(9) and a(10) from Alexander Hulpke, Dec 03 2004
More terms from a(11) and a(12) added by Christian G. Bower, Feb 23 2006 based on Goetz Pfeiffer's web page.
a(13) added by Liam Naughton, Jun 09 2011
a(14)-a(18) from Holt reference, Wouter Meeussen, Jul 02 2013

A005226 Number of atomic species of degree n; also number of connected permutation groups of degree n.

Original entry on oeis.org

0, 1, 1, 2, 6, 6, 27, 20, 130, 124, 598, 641, 4850, 4772, 35625, 46074, 389839, 487408, 4617554
Offset: 0

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Author

Keywords

Comments

An atomic species is one that is not the product of smaller species. - Christian G. Bower, Feb 23 2006
A permutation group is connected if it is not the direct product of smaller permutation groups. - Christian G. Bower, Feb 23 2006

References

  • F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Camb. 1998, p. 147.
  • Jacques Labelle, Quelques espèces sur les ensembles de petite cardinalité, Ann. Sc. Math. Québec 9.1 (1985): 31-58.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A005227. Unlabeled version of A116655.

Programs

  • Mathematica
    A000638 = Cases[Import["https://oeis.org/A000638/b000638.txt", "Table"], {, }][[All, 2]];
    (* EulerInvTransform is defined in A022562 *)
    {0} ~Join~ EulerInvTransform[A000638 // Rest] (* Jean-François Alcover, Dec 03 2019, updated Mar 17 2020 *)

Formula

Inverse Euler transform of A000638. Define b(n), c(n), d(): b(1)=d(1)=0. b(k)=A005227(k), k>1. c(k)=A000638(k), k>0. d(k)=a(k), k>1. d is Dirichlet convolution of b and c. - Christian G. Bower, Feb 23 2006

Extensions

a(11) corrected and a(12) added by Christian G. Bower, Feb 23 2006 based on Goetz Pfeiffer's edit to A000638.
Could be extended to a(18) now using the new terms for A000637. - N. J. A. Sloane, Jul 30 2010
a(13) from Liam Naughton, Nov 23 2012
a(14)-a(18) from the inverse Euler transform of A000637. - R. J. Mathar, Mar 03 2015
Showing 1-2 of 2 results.