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 A136794 #9 Dec 13 2018 11:32:04 %S A136794 2,8,52,376,2998,25256,222128,2013680,18691522,176743160,1696546848, %T A136794 16488151400,161919802562,1604274741608,16016845623764, %U A136794 160977882238968,1627406260427490,16537733701226936 %N A136794 Number of unlabeled marked rooted trees with n nodes. %C A136794 A marked rooted tree is a rooted tree where each node and edge is marked as + or -. %D A136794 F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 293 (4.1.60). %H A136794 L. Foissy, <a href="https://arxiv.org/abs/1811.07572">Algebraic structures on typed decorated rooted trees</a>, arXiv:1811.07572 (2018) %H A136794 <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a> %F A136794 a(n) = A136793(n)/2 = A052763(n)*2. %Y A136794 Cf. A136795 (tree version), A136796 (labeled version). %K A136794 nonn %O A136794 1,1 %A A136794 _Christian G. Bower_, Jan 21 2008