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 A052877 #17 Apr 18 2017 07:04:12
%S A052877 0,2,3,7,27,151,1083,9367,94587,1091671,14174523,204495127,3245265147,
%T A052877 56183135191,1053716696763,21282685940887,460566381955707,
%U A052877 10631309363962711,260741534058271803,6771069326513690647
%N A052877 E.g.f.: exp(x)-1+log(-1/(-2+exp(x))).
%C A052877 Previous name was: A simple grammar.
%H A052877 INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=848">Encyclopedia of Combinatorial Structures 848</a>
%F A052877 E.g.f.: exp(x)-1+log(-1/(-2+exp(x)))
%F A052877 a(n) ~ (n-1)! / log(2)^n. - _Vaclav Kotesovec_, Sep 30 2013
%p A052877 spec := [S,{B=Set(Z,1 <= card),C=Cycle(B),S=Union(B,C)},labeled]: seq(combstruct[count](spec, size=n), n=0..20);
%t A052877 CoefficientList[Series[E^x-1+Log[-1/(-2+E^x)], {x, 0, 20}], x]* Range[0, 20]! (* _Vaclav Kotesovec_, Sep 30 2013 *)
%Y A052877 a(n) = A000629(n-1)+1, n>0. Cf. A002050.
%K A052877 easy,nonn
%O A052877 0,2
%A A052877 encyclopedia(AT)pommard.inria.fr, Jan 25 2000
%E A052877 New name, using e.g.f., from _Vaclav Kotesovec_, Sep 30 2013