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 A193098 #7 Mar 30 2012 18:37:27 %S A193098 1,1,3,18,171,2283,39942,874944,23243829,731486637,26782956144, %T A193098 1124838704976,53567894139165,2865318598843281,170774893724336223, %U A193098 11264050942430761881,817374450539598433587,64917115563124199691834 %N A193098 E.g.f. A(x) satisfies: A'(x) = 1 + A(A(A(x))). %e A193098 E.g.f.: A(x) = x + x^2/2! + 3*x^3/3! + 18*x^4/4! + 171*x^5/5! + 2283*x^6/6! +... %e A193098 where the derivative of the e.g.f. begins: %e A193098 A'(x) = 1 + x + 3*x^2/2! + 18*x^3/3! + 171*x^4/4! + 2283*x^5/5! +... %e A193098 Related expansions. %e A193098 A(A(x)) = x + 2*x^2/2! + 9*x^3/3! + 69*x^4/4! + 777*x^5/5! + 11802*x^6/6! + 229047*x^7/7! + 5472600*x^8/8! +... %e A193098 A(A(A(x))) = x + 3*x^2/2! + 18*x^3/3! + 171*x^4/4! + 2283*x^5/5! +... %o A193098 (PARI) {a(n)=local(A=x); for(i=1, n, A=intformal(1+subst(A, x, subst(A, x, A+O(x^(n+1)))))); n!*polcoeff(A, n)} %Y A193098 Cf. A001028, A193099, A193100, A179420. %K A193098 nonn %O A193098 1,3 %A A193098 _Paul D. Hanna_, Jul 15 2011