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 A324768 #8 Jun 20 2020 02:46:44
%S A324768 1,1,2,3,6,11,27,60,152,376,968,2492,6549,17259,46000,123214,332304,
%T A324768 900406,2451999,6703925
%N A324768 Number of fully anti-transitive rooted trees with n nodes.
%C A324768 An unlabeled rooted tree is fully anti-transitive if no proper terminal subtree of any branch of the root is a branch of the root.
%e A324768 The a(1) = 1 through a(6) = 11 rooted trees:
%e A324768 o (o) (oo) (ooo) (oooo) (ooooo)
%e A324768 ((o)) ((oo)) ((ooo)) ((oooo))
%e A324768 (((o))) (((oo))) (((ooo)))
%e A324768 ((o)(o)) ((o)(oo))
%e A324768 ((o(o))) ((o(oo)))
%e A324768 ((((o)))) ((oo(o)))
%e A324768 ((((oo))))
%e A324768 (((o)(o)))
%e A324768 (((o(o))))
%e A324768 ((o((o))))
%e A324768 (((((o)))))
%t A324768 rtall[n_]:=Union[Sort/@Join@@(Tuples[rtall/@#]&/@IntegerPartitions[n-1])];
%t A324768 Table[Length[Select[rtall[n],Intersection[Union@@Rest[FixedPointList[Union@@#&,#]],#]=={}&]],{n,10}]
%Y A324768 Cf. A000081, A279861, A290689, A304360, A306844, A318185.
%Y A324768 Cf. A324695, A324751, A324756, A324758, A324763, A324765, A324769, A324770.
%Y A324768 Cf. A324838, A324840, A324844, A324846.
%K A324768 nonn,more
%O A324768 1,3
%A A324768 _Gus Wiseman_, Mar 17 2019
%E A324768 a(17)-a(20) from _Jinyuan Wang_, Jun 20 2020