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 A111551 #3 Mar 30 2012 18:36:50
%S A111551 0,3,9,47,321,2607,24099,247527,2783331,33924303,445016619,6249234807,
%T A111551 93541817331,1487200667103,25037315924859,445123900236807,
%U A111551 8336458657796931,164100631571947503,3388128151043405259
%N A111551 Column 2 of A111549, which is the matrix log of A111544.
%o A111551 (PARI) {a(n)=local(M=matrix(n+3,n+3,m,j,if(m==j,1,if(m==j+1,-m+1, -(m-j-1)*polcoeff(log(sum(i=0,m,(i+2)!/2!*x^i)),m-j-1))))); if(n<0,0,sum(i=1,#M,(M^0-M)^i/i)[n+3,3])}
%Y A111551 Cf. A111549, A111544.
%K A111551 nonn
%O A111551 0,2
%A A111551 _Paul D. Hanna_, Aug 07 2005