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 A224917 #27 Feb 19 2024 22:55:08 %S A224917 1,1,1,2,5,15,64,342,2344,19137,181204,1927017,22652805,290392448, %T A224917 4022276630,59749492128,946174967813,15892939156209 %N A224917 Stable k-tree numbers. %C A224917 a(n) is the number of unlabeled k-trees with n+k vertices for all k >= n-2. %C A224917 A k-tree is recursively defined as follows: The complete graph K_k is a k-tree and a k-tree on n+1 vertices is obtained by joining a vertex to a k-clique in a k-tree on n vertices. %H A224917 Allan Bickle, <a href="https://doi.org/10.20429/tag.2024.000105">A Survey of Maximal k-degenerate Graphs and k-Trees</a>, Theory and Applications of Graphs 0 1 (2024) Article 5. %H A224917 A. Gainer-Dewar, <a href="http://www.combinatorics.org/ojs/index.php/eljc/article/view/v19i4p45/0">Γ-species and the enumeration of k-trees</a>, Electron. J. Combin. 19, no. 4, (2012), P45. %H A224917 I. M. Gessel and A. Gainer-Dewar, <a href="http://arxiv.org/abs/1309.1429">Counting unlabeled k-trees</a>, arXiv:1309.1429 [math.CO], 2013-2014. %H A224917 I. M. Gessel and A. Gainer-Dewar, <a href="https://doi.org/10.1016/j.jcta.2014.05.002">Counting unlabeled k-trees</a>, J. Combin. Theory Ser. A 126 (2014), 177-193. %Y A224917 Cf. A000055 (unlabeled trees), A054581 (unlabeled 2-trees), A078792 (unlabeled 3-trees), A078793 (unlabeled 4-trees), A201702 (unlabeled 5-trees), A202037 (unlabeled 6-trees). %K A224917 nonn,more %O A224917 0,4 %A A224917 _Ira M. Gessel_, Apr 19 2013