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 A052764 #22 Nov 08 2017 11:33:49
%S A052764 0,1,8,144,4096,160000,7962624,481890304,34359738368,2821109907456,
%T A052764 262144000000000,27197360938418176,3116402981210161152,
%U A052764 390877006486250192896,53265296773103187132416,7836416409600000000000000,1237940039285380274899124224,208998227690370098316628197376
%N A052764 E.g.f.: -1/4*LambertW(-4*x).
%C A052764 Previous name was: A simple grammar.
%H A052764 G. C. Greubel, <a href="/A052764/b052764.txt">Table of n, a(n) for n = 0..320</a>
%H A052764 INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=721">Encyclopedia of Combinatorial Structures 721</a>
%F A052764 E.g.f.: -1/4*LambertW(-4*x).
%F A052764 For n>0, a(n) = 2^(2*n-2)*n^(n-1). - _Vaclav Kotesovec_, Sep 30 2013
%F A052764 a(n) = [x^n] x/(1 - 4*n*x). - _Ilya Gutkovskiy_, Oct 12 2017
%p A052764 spec := [S,{B=Set(S),S=Prod(Z,B,B,B,B)},labeled]: seq(combstruct[count](spec,size=n), n=0..20);
%t A052764 CoefficientList[Series[-1/4*LambertW[-4*x], {x, 0, 20}], x]* Range[0, 20]! (* _Vaclav Kotesovec_, Sep 30 2013 *)
%o A052764 (PARI) x='x+O('x^50); concat([0], Vec(serlaplace((-1/4)*lambertw(-4*x)))) \\ _G. C. Greubel_, Nov 07 2017
%K A052764 easy,nonn
%O A052764 0,3
%A A052764 encyclopedia(AT)pommard.inria.fr, Jan 25 2000
%E A052764 New name using e.g.f. by _Vaclav Kotesovec_, Sep 30 2013