来自在线整数百科全书的问候语!http://oeis.org/ Search: id:a051748 Showing 1-1 of 1 %I A051748 %S A051748 0,1,2,7,13,34,72,137,249,524,953,1679,3106,5270,9398,15666,26284, %T A051748 43409,72861,115940,189476,297929,476904,743094,1174624,1782368, %U A051748 2787256,4196505,6413986,9645485,14553197,21483398,32243250,47165359,69606943 %N A051748 Number of character table entries of the symmetric group S_n which are < 0. %t A051748 a[n_] := Count[FiniteGroupData[{"SymmetricGroup", n}, "CharacterTable"], _?Negative, 2]; Array[a, 10] (* _Jean-François Alcover_, Apr 03 2017 *) %o A051748 (GAP) A051748 := n -> Sum(Irr(CharacterTable("Symmetric", n)), chi -> Number(chi, x->x<0)); # _Eric M. Schmidt_, Jul 14 2012, revised Sep 05 2012 %Y A051748 Cf. A006907, A051749. %K A051748 nonn,nice %O A051748 1,3 %A A051748 JOHN MCKAY (mckay(AT)cs.concordia.ca), Dec 08 1999 %E A051748 More terms from _Eric M. Schmidt_, Jul 14 2012 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE