A006908 - OEIS

A006908

Number of nonzero elements in the character table of the symmetric group S_n.
(Formerly M3338)

1, 4, 8, 21, 39, 92, 170, 331, 593, 1176, 2118, 3699, 6658, 11347, 19760, 32746, 54854, 90245, 149906, 237953, 387937, 608531, 970912, 1510331, 2380015, 3610620, 5634251, 8474110, 12934092, 19440955, 29291690, 43233800, 64825830, 94779612, 139820232

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

John McKay (email to N. J. A. Sloane, Apr 23 2013) observes that A061256 and A006908 coincide for a surprising number of terms, and asks for an explanation. - N. J. A. Sloane, May 19 2013

REFERENCES

J. McKay, personal communication to N. J. A. Sloane, circa 1991.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=1..35.

MATHEMATICA

a[n_] := Count[FiniteGroupData[{"SymmetricGroup", n}, "CharacterTable"], k_ /; k != 0, 2]; Array[a, 10] (* Jean-François Alcover, Oct 21 2016 *)

PROG

(GAP) A006908 := n -> Sum(Irr(CharacterTable("Symmetric", n)), chi -> Number(chi, x->x<>0)); # Eric M. Schmidt, Jul 13 2012, revised Sep 05 2012

CROSSREFS

Cf. A006907, A061256.

Sequence in context: A037020 A094878 A233401 * A079860 A061256 A180608