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 A203267 #9 Sep 24 2024 14:42:36 %S A203267 1,7,46,371,2611,22444,163010,1414763,10666423,92901977,700765693, %T A203267 6267591344,47400875250,421269688378,3261487427911,28956966303371, %U A203267 222519855315655,2011947117233155,15451470070634425,138876292766145541,1085821838608348370,9706788507990083429 %N A203267 L.g.f.: Sum_{n>=1} a(n)*x^n/n = Sum_{n>=1} x^n/n * exp( Sum_{k>=1} 3*a(n*k)*x^(n*k)/k ). %C A203267 L.g.f.: Sum_{n>=1} a(n)*x^n/n = Sum_{n>=1} G_n(x^n)^3 * x^n/n where G_n(x) = exp( Sum_{k>=1} a(n*k)*x^k/k ) are integer series. %F A203267 Equals the logarithmic derivative of A203268. %e A203267 L.g.f.: L(x) = x + 7*x^2/2 + 46*x^3/3 + 371*x^4/4 + 2611*x^5/5 +... %e A203267 L.g.f.: L(x) = Sum_{n>=1} a(n)*x^n/n = Sum_{n>=1} G_n(x^n)^3*x^n/n %e A203267 where G_n(x) = exp( Sum_{k>=1} a(n*k)*x^k/k ), which begin: %e A203267 G_1(x) = 1 + x + 4*x^2 + 19*x^3 + 116*x^4 + 683*x^5 + 4818*x^6 +... %e A203267 G_2(x) = 1 + 7*x + 210*x^2 + 8837*x^3 + 427910*x^4 + 22758491*x^5 +...; %e A203267 G_3(x) = 1 + 46*x + 12280*x^2 + 4087909*x^3 + 1805475734*x^4 +...; %e A203267 G_4(x) = 1 + 371*x + 776202*x^2 + 2360146453*x^3 +...; %e A203267 G_5(x) = 1 + 2611*x + 49859649*x^2 + 1211412677799*x^3 +...; %e A203267 G_6(x) = 1 + 22444*x + 3385662240*x^2 + 742868246890817*x^3 +...; %e A203267 G_7(x) = 1 + 163010*x + 223920974239*x^2 + 396998122840515180*x^3 +...; ... %o A203267 (PARI) {a(n)=local(L=vector(n, i, 1)); for(i=1, n, L=Vec(deriv(sum(m=1, n, x^m/m*exp(sum(k=1, floor(n/m), 3*L[m*k]*x^(m*k)/k)+x*O(x^n)))))); L[n]} %Y A203267 Cf. A203268 (exp), A203253, A203265. %K A203267 nonn %O A203267 1,2 %A A203267 _Paul D. Hanna_, Dec 30 2011