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 A378280 #11 Nov 27 2024 12:33:31 %S A378280 0,0,0,1,5,60,560,5740,58716,734160,8337120,133212420,1769490580 %N A378280 Number of subgroups of S_n isomorphic to S_4, where S_n is the n-th symmetric group. %o A378280 (GAP) A378280 := function(n) %o A378280 local S; %o A378280 S := SymmetricGroup(n); %o A378280 return Sum(IsomorphicSubgroups(S, SymmetricGroup(4)), x->Index(S, Normalizer(S, Image(x)))); %o A378280 end; # See A378163 %Y A378280 Column k=4 of A378163. %Y A378280 Cf. A000085, A378279, A378281. %K A378280 nonn,hard,more %O A378280 1,5 %A A378280 _Jianing Song_, Nov 21 2024