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 A305839 #7 Jun 11 2018 14:29:04 %S A305839 1,1,3,6,15,32,77,172,405,930,2180,5070,11914,27929,65829,155202, %T A305839 367053,868990,2061723,4897502,11652547,27757960,66210042,158103242, %U A305839 377957299,904439542,2166408422,5193894809,12463003846,29929966312,71933014935,173009938416 %N A305839 Number of unlabeled forests of rooted trees with 2n edges and n connected components, in which the outdegree of each node is <= 2 and the symmetric group acts on the components. %H A305839 Alois P. Heinz, <a href="/A305839/b305839.txt">Table of n, a(n) for n = 0..400</a> %F A305839 a(n) = A088326(2n,n) = A088326(2n+k,n+k) for k >= 0. %Y A305839 Cf. A088326. %K A305839 nonn %O A305839 0,3 %A A305839 _Alois P. Heinz_, Jun 11 2018