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 A171005 #19 Oct 14 2023 12:11:42
%S A171005 4,15,72,420,2880,22680,201600,1995840,21772800,259459200,3353011200,
%T A171005 46702656000,697426329600,11115232128000,188305108992000,
%U A171005 3379030566912000,64023737057280000,1277273554292736000,26761922089943040000,587545834974658560000,13488008733331292160000
%N A171005 a(n) = (n+1)*(n-1)!/2.
%C A171005 A wheel graph is a graph with n+1 vertices (n>=3) formed by connecting a single vertex to all vertices of an n-cycle. a(n) is the number of labeled wheel graphs. - _Geoffrey Critzer_, Feb 02 2014
%F A171005 a(n) = Sum_{j=0..n} (-1)^(n-j)*binomial(n,j)*(j+1)^(n+1)/(n+1). - _Vladimir Kruchinin_, Jun 01 2013
%F A171005 D-finite with recurrence -n*a(n) +(n-1)*(n+1)*a(n-1) = 0. - _R. J. Mathar_, Feb 01 2022
%e A171005 For n >= 1, the sequence is 1, 3/2, 4, 15, 72, 420, 2880, 22680, 201600, 1995840, ...
%t A171005 Table[((n+1)*(n-1)!)/2,{n,3,30}] (* _Vladimir Joseph Stephan Orlovsky_, Apr 03 2011 *)
%t A171005 nn=20;Drop[Range[0,nn]!CoefficientList[Series[x (Log[1/(1-x)]/2+x^2/4+x/2),{x,0,nn}],x],4] (* _Geoffrey Critzer_, Feb 02 2014 *)
%Y A171005 Equals A001048/2.
%K A171005 nonn,easy
%O A171005 3,1
%A A171005 _N. J. A. Sloane_, Sep 02 2010