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 A324765 #6 Mar 18 2019 08:15:10
%S A324765 1,1,2,3,6,11,26,52,119,266,618,1432,3402,8093,19505,47228,115244,
%T A324765 282529,696388,1723400
%N A324765 Number of recursively anti-transitive rooted trees with n nodes.
%C A324765 An unlabeled rooted tree is recursively anti-transitive if no branch of a branch of a terminal subtree is a branch of the same subtree.
%e A324765 The a(1) = 1 through a(6) = 11 recursively anti-transitive rooted trees:
%e A324765 o (o) (oo) (ooo) (oooo) (ooooo)
%e A324765 ((o)) ((oo)) ((ooo)) ((oooo))
%e A324765 (((o))) (((oo))) (((ooo)))
%e A324765 ((o)(o)) ((o)(oo))
%e A324765 (o((o))) (o((oo)))
%e A324765 ((((o)))) (oo((o)))
%e A324765 ((((oo))))
%e A324765 (((o)(o)))
%e A324765 ((o((o))))
%e A324765 (o(((o))))
%e A324765 (((((o)))))
%t A324765 nallt[n_]:=Select[Union[Sort/@Join@@(Tuples[nallt/@#]&/@IntegerPartitions[n-1])],Intersection[Union@@#,#]=={}&];
%t A324765 Table[Length[nallt[n]],{n,10}]
%Y A324765 Cf. A000081, A290689, A301700, A304360, A306844, A317787, A318185.
%Y A324765 Cf. A324695, A324751, A324756, A324758, A324764, A324766, A324767, A324768.
%Y A324765 Cf. A324838, A324840, A324844.
%K A324765 nonn,more
%O A324765 1,3
%A A324765 _Gus Wiseman_, Mar 17 2019