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 A091106 #1 Feb 19 2004 03:00:00
%S A091106 -1,-1,0,8,78,764,8310,100988,1362438,20246444,328972470,5805917468,
%T A091106 110645911398,2265191981324,49589790516630,1156201277261948,
%U A091106 28605950745797958,748605590542359404,20661245832389468790,599820758571599742428,18272940402442730318118
%N A091106 a(0)=a(1)=-1. For n>1: a(n)=Sum(i!i^2 Stirling2[n-1,i],i=2,..,n-1).
%F A091106 E.g.f.: (exp(x)-1)^2/(2(exp(x)-2)^2)-exp(x). a(n)=(1/2)(A069321(n)-A000670(n))-1.
%t A091106 CoefficientList[Series[(1/2)((Exp[x]-1)/(Exp[x]-2))^2-Exp[x], {x, 0, 20}], x]
%K A091106 easy,sign
%O A091106 0,4
%A A091106 Mario Catalani (mario.catalani(AT)unito.it), Dec 19 2003