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 1-5 of 5 results.

A029725 Number of distinct subgroups of alternating group A_n, counting conjugates as distinct.

Original entry on oeis.org

1, 1, 1, 2, 10, 59, 501, 3786, 48337, 508402, 6469142, 81711572, 2019160542, 31945830446, 749115591093, 15230426073946, 617313283787616, 13472047923890487
Offset: 0

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Author

Keywords

Crossrefs

Cf. A005432. Labeled version of A029726.

Programs

  • Magma
    n := 5; &+[ Length(s):s in SubgroupLattice(Alt(n)) ];

Formula

Exponential transform of A116652. - Christian G. Bower, Feb 23 2006

Extensions

a(9)-a(13) added by Christian G. Bower, Feb 23 2006 based on Goetz Pfeiffer's web page.
a(14)-a(17) from Vaclav Kotesovec, Jul 21 2022

A116653 Number of connected even permutation groups; conjugacy classes of connected subgroups of the alternating group A_n; atomic species based on even permutation groups.

Original entry on oeis.org

0, 1, 0, 1, 3, 4, 12, 15, 87, 61, 143, 168, 1254, 1079, 5281, 7619, 56670, 58957
Offset: 0

Views

Author

Christian G. Bower, Feb 23 2006

Keywords

Crossrefs

Unlabeled version of A116652.

Formula

Inverse Euler transform of A029726. Define b(n), c(n): b(1)=c(0)=0. b(k)=A116654(k), k>1. c(k)=A029726(k), k>0. a(n) is Dirichlet convolution of b and c.

Extensions

a(14)-a(17) from Vaclav Kotesovec, Jul 21 2022

A066113 a(n) is the number of conjugacy classes of maximal subgroups of the alternating group A_n.

Original entry on oeis.org

0, 1, 2, 3, 5, 5, 6, 8, 7, 7, 11, 9, 9, 11, 12, 10, 13, 10, 14, 14, 13, 13, 19, 15, 15, 18, 20, 15, 21, 20, 22, 20, 18, 21, 27, 19, 21, 21, 27, 21, 27, 22, 26, 29, 24, 24, 32, 27, 31, 27, 31, 27, 33, 30, 35, 34, 30, 30, 41, 31, 33, 40, 40, 41, 40, 34, 39, 36, 40
Offset: 2

Views

Author

Reiner Martin, Dec 30 2001

Keywords

Crossrefs

Programs

  • GAP
    List([2..50],i->Length(MaximalSubgroupClassReps(AlternatingGroup(i))));

Extensions

More terms from Alexander Hulpke, Feb 19 2002
Terms a(51) and beyond from Andrew Howroyd, Jul 02 2018

A070733 Size of largest conjugacy class in A_n, the alternating group on n symbols.

Original entry on oeis.org

1, 1, 1, 4, 20, 90, 630, 3360, 30240, 226800, 2494800, 23950080, 311351040, 3632428800, 54486432000, 747242496000, 12703122432000, 200074178304000, 3801409387776000, 67580611338240000, 1419192838103040000, 28100018194440192000, 646300418472124416000
Offset: 1

Views

Author

Sharon Sela (sharonsela(AT)hotmail.com), May 14 2002

Keywords

Comments

For n > 5, the largest conjugacy class in A_n corresponds to the cycle type (n-2, 2) if n is even, (n-3, 2, 1) if n is odd. - Eric M. Schmidt, Sep 13 2014

Crossrefs

Programs

  • GAP
    a:=function(n)
    local G,CC,SCC,SCC1;
    G:=AlternatingGroup(n);
    CC:=ConjugacyClasses(G);;
    SCC:=List(CC,Size);
    return Maximum(SCC);
    end;;  #  W. Edwin Clark, Feb 02 2014
    
  • Mathematica
    a[n_] := (n!/2) / If[OddQ[n],  n-3, n-2]; a[1] = a[2] = a[3] = 1; a[4] = 4; a[5] = 20; Array[a, 20] (* Amiram Eldar, Jul 12 2025 *)
  • PARI
    a(n) = if(n < 6, [1, 1, 1, 4, 20][n], (n!/2) / if(n % 2,  n-3, n-2)); \\ Amiram Eldar, Jul 12 2025

Formula

For n > 5, a(n) = n!/(2(n-2)) if n is even, a(n) = n!/(2(n-3)) if n is odd. - Eric M. Schmidt, Sep 13 2014
Sum_{n>=1} 1/a(n) = 111/10 + 1/e - 3*e. - Amiram Eldar, Jul 12 2025

Extensions

More terms from Eric M. Schmidt, Sep 13 2014

A116654 Number of atomic species based on even permutation groups that are not substitutions of smaller species.

Original entry on oeis.org

0, 1, 0, 1, 3, 4, 11, 15, 84, 59, 139, 168, 1232, 1079
Offset: 0

Views

Author

Christian G. Bower, Feb 23 2006

Keywords

Formula

Define b(n), c(n): b(1)=c(0)=0. b(k)=a(k), k>1. c(k)=A029726(k), k>0. A116653(n) is Dirichlet convolution of b and c.
Showing 1-5 of 5 results.