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 A066586 #6 Sep 22 2013 06:24:09 %S A066586 2,6,9,11,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, %T A066586 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, %U A066586 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9 %N A066586 Number of normal subgroups of the group of n X n signed permutations matrices (described in sequence A066051). %C A066586 The similar sequence for the "ordinary" symmetric group S_n is 1, 2, 3, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, ... %F A066586 For n>=5 a(n) = 9. %Y A066586 Cf. A066051. %K A066586 nonn %O A066586 1,1 %A A066586 Sharon Sela (sharonsela(AT)hotmail.com), Jan 07 2002