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.
%I A006908 M3338 #32 Dec 19 2021 00:18:15 %S A006908 1,4,8,21,39,92,170,331,593,1176,2118,3699,6658,11347,19760,32746, %T A006908 54854,90245,149906,237953,387937,608531,970912,1510331,2380015, %U A006908 3610620,5634251,8474110,12934092,19440955,29291690,43233800,64825830,94779612,139820232 %N A006908 Number of nonzero elements in the character table of the symmetric group S_n. %C A006908 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 %D A006908 J. McKay, personal communication to N. J. A. Sloane, circa 1991. %D A006908 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %t A006908 a[n_] := Count[FiniteGroupData[{"SymmetricGroup", n}, "CharacterTable"], k_ /; k != 0, 2]; Array[a, 10] (* _Jean-François Alcover_, Oct 21 2016 *) %o A006908 (GAP) A006908 := n -> Sum(Irr(CharacterTable("Symmetric", n)), chi -> Number(chi, x->x<>0)); # _Eric M. Schmidt_, Jul 13 2012, revised Sep 05 2012 %Y A006908 Cf. A006907, A061256. %K A006908 nonn,nice %O A006908 1,2 %A A006908 _Simon Plouffe_ and _N. J. A. Sloane_ %E A006908 More terms from _Eric M. Schmidt_, Jul 13 2012