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 A193100 #9 Mar 30 2012 18:37:27 %S A193100 1,3,63,6804,1990170,1145276496,1172421884088,1981846981092069, %T A193100 5166650461467914874,19710026486212156729362, %U A193100 105613632141369240315500892,768455476842781911036557334267,7380326961188107570497477933701847 %N A193100 E.g.f. A(x) satisfies: A’(x) = x + A(A(x)), where A(x) = Sum_{n>=0} a(n)*x^(3*n+2)/(3*n+2)!. %e A193100 E.g.f.: A(x) = x^2/2! + 3*x^5/5! + 63*x^8/8! + 6804*x^11/11! + 1990170*x^14/14! + 1145276496*x^17/17! + 1172421884088*x^20/20! +... %e A193100 where A'(x) = x + 3*x^4/4! + 63*x^7/7! + 6804*x^10/10! +... %e A193100 and A(A(x)) = 3*x^4/4! + 63*x^7/7! + 6804*x^10/10! + 1990170*x^13/13! +... %o A193100 (PARI) {a(n)=local(A=x^2/2);for(i=1,n,A=intformal(x+subst(A,x,A+O(x^(3*n+3)))));(3*n+2)!*polcoeff(A,3*n+2)} %Y A193100 Cf. A001028, A179420. %K A193100 nonn %O A193100 0,2 %A A193100 _Paul D. Hanna_, Jul 15 2011