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 1-3 of 3 results.

A001228 Orders of sporadic simple groups.

Original entry on oeis.org

7920, 95040, 175560, 443520, 604800, 10200960, 44352000, 50232960, 244823040, 898128000, 4030387200, 145926144000, 448345497600, 460815505920, 495766656000, 42305421312000, 64561751654400, 273030912000000, 51765179004000000, 90745943887872000, 4089470473293004800, 4157776806543360000, 86775571046077562880, 1255205709190661721292800, 4154781481226426191177580544000000, 808017424794512875886459904961710757005754368000000000
Offset: 1

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Keywords

Comments

Numbers of divisors: A174601(n) = A000005(a(n)); squarefree kernels: A174848(n) = A007947(a(n)). - Reinhard Zumkeller, Apr 02 2010
By historical convention, the Tits group is often excluded from the list of sporadic simple groups. It could be inserted as a(7) = 17971200 giving this sequence 27 rather than 26 elements. - Charles R Greathouse IV, Jul 09 2020

Examples

			The first term is 7920 because the order of the sporadic group M_{11} is 7920, the smallest order of any sporadic group.
		

References

  • J. H. Conway, R. T. Curtis, S. P. Norton, R. A. Parker and R. A. Wilson, ATLAS of Finite Groups. Oxford Univ. Press, 1985 [for best online version see https://oeis.org/wiki/Welcome#Links_to_Other_Sites].
  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 296.
  • Martin Gardner, "The Last Recreations", 1997, chap 9, p. 153.

Crossrefs

Extensions

Entries checked by Pab Ter (pabrlos(AT)yahoo.com), May 29 2004

A002267 The 15 supersingular primes: primes dividing order of Monster simple group.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 41, 47, 59, 71
Offset: 1

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Comments

The supersingular primes are a subset of the Chen primes (A109611). - Paul Muljadi, Oct 12 2005
PROD(a(k): 1<=k<=15) = 1618964990108856390 = A174848(26). - Reinhard Zumkeller, Apr 02 2010

References

  • J. H. Conway, R. T. Curtis, S. P. Norton, R. A. Parker and R. A. Wilson, ATLAS of Finite Groups. Oxford Univ. Press, 1985 [for best online version see https://oeis.org/wiki/Welcome#Links_to_Other_Sites].
  • A. P. Ogg, Modular functions, in The Santa Cruz Conference on Finite Groups (Univ. California, Santa Cruz, Calif., 1979), pp. 521-532, Proc. Sympos. Pure Math., 37, Amer. Math. Soc., Providence, R.I., 1980.

Crossrefs

Programs

  • Mathematica
    FactorInteger[GroupOrder[MonsterGroupM[]]][[All, 1]] (* Jean-François Alcover, Oct 03 2016 *)
  • PARI
    A002267=vecextract(primes(20),612351) \\ bitmask 2^20-1-213<<11: remove primes # 12, 14, 16, 18 and 19. - M. F. Hasler, Nov 10 2017

A321224 Sporadic numbers: n is defined to be sporadic if the set of groups G not in {A_n, S_n} and having a core-free maximal subgroup of index n is nonempty and contains only sporadic simple groups.

Original entry on oeis.org

266, 506, 759, 1045, 1288, 1463, 3795
Offset: 1

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Author

Sébastien Palcoux, Aug 27 2019

Keywords

Comments

A finite group G has a core-free maximal subgroup H of index n if and only if it is a primitive permutation group of degree n (acting on the set G/H of cosets).
There are no other sporadic numbers less than 4096 (see computation below).
According to Derek Holt, the next sporadic number is 4180, and the last one should be 492693551703971265784426771318116315247411200000000 (coming from the maximal subgroup 41:40 of the Monster, and assuming that L_2(13) is not maximal).
Derek Holt suggested another sequence where we also allow the extensions of the sporadic simple groups.

References

  • The GAP Group, GAP - Groups, Algorithms, and Programming, Version 4.9.3, 2018. gap-system.org.

Crossrefs

Programs

  • GAP
    IsSporadic:=function(G)
       if not IsSimple(G) then
          return false;
       else
          return IsomorphismTypeInfoFiniteSimpleGroup(G).series="Spor";
       fi;
    end;;
    SporadicNumbers:=function(b1,b2)
       local L,i,n,a,j,G;
       L:=[];
       for i in [b1..b2] do
          n:=NrPrimitiveGroups(i);
          if n>2 then
             a:=0;
             for j in [1..n] do
                G:=PrimitiveGroup(i,j);
                if not G=SymmetricGroup(i) and not G=AlternatingGroup(i) and not IsSporadic(G) then
                   a:=1;
                   break;
                fi;
             od;
             if a=0 then
                Add(L,i);
             fi;
          fi;
       od;
       return L;
    end;;
    SporadicNumbers(1,4095);
    # gives: [ 266, 506, 759, 1045, 1288, 1463, 3795 ]
Showing 1-3 of 3 results.