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 A111558 #3 Mar 30 2012 18:36:50
%S A111558 1,2,9,60,509,5034,55689,674624,8838189,124199454,1861297049,
%T A111558 29618273604,498716980989,8860512190034,165694162575369,
%U A111558 3254269731689064,66994569450549869,1443024570035017254
%N A111558 Row sums of triangle A111553.
%o A111558 (PARI) {a(n)=if(n<0,0,sum(k=1,n+1,(matrix(n+k,n+k,m,j,if(m==j,1,if(m==j+1,-m+1, -(m-j-1)*polcoeff(log(sum(i=0,m,(i+3)!/3!*x^i)),m-j-1))))^-1)[n+1,k]))}
%Y A111558 Cf. A111553.
%K A111558 nonn
%O A111558 0,2
%A A111558 _Paul D. Hanna_, Aug 07 2005