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 A363543 #9 Jun 09 2023 08:54:23
%S A363543 1,4,7,23,69,234,826,3000,11168,42313,162829,634052,2495051,9903761,
%T A363543 39612048,159481988,645833656,2628829700,10749777653,44139474552,
%U A363543 181916530895,752288709592,3120574260606,12981015704961,54138655342763,226330448292140
%N A363543 G.f. satisfies A(x) = exp( Sum_{k>=1} (-1)^(k+1) * (3^k + A(x^k)) * x^k/k ).
%F A363543 A(x) = Sum_{k>=0} a(k) * x^k = (1+3*x) * Product_{k>=0} (1+x^(k+1))^a(k).
%F A363543 a(0) = 1; a(n) = (-1/n) * Sum_{k=1..n} ( (-3)^k + Sum_{d|k} (-1)^(k/d) * d * a(d-1) ) * a(n-k).
%o A363543 (PARI) seq(n) = my(A=1); for(i=1, n, A=exp(sum(k=1, i, (-1)^(k+1)*(3^k+subst(A, x, x^k))*x^k/k)+x*O(x^n))); Vec(A);
%Y A363543 Cf. A038075, A363542.
%Y A363543 Cf. A363509, A363541.
%K A363543 nonn
%O A363543 0,2
%A A363543 _Seiichi Manyama_, Jun 09 2023