The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A324840 Number of fully recursively anti-transitive rooted trees with n nodes. 9
 1, 1, 2, 3, 5, 7, 14, 23, 46, 85, 165, 313, 625, 1225, 2459, 4919, 9928, 20078, 40926, 83592 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS An unlabeled rooted tree is fully recursively anti-transitive if no proper terminal subtree of any terminal subtree is a branch of the larger subtree. LINKS EXAMPLE The a(1) = 1 through a(7) = 14 fully recursively anti-transitive rooted trees:   o  (o)  (oo)   (ooo)    (oooo)     (ooooo)      (oooooo)           ((o))  ((oo))   ((ooo))    ((oooo))     ((ooooo))                  (((o)))  (((oo)))   (((ooo)))    (((oooo)))                           ((o)(o))   ((o)(oo))    ((o)(ooo))                           ((((o))))  ((((oo))))   ((oo)(oo))                                      (((o)(o)))   ((((ooo))))                                      (((((o)))))  (((o))(oo))                                                   (((o)(oo)))                                                   ((o)((oo)))                                                   ((o)(o)(o))                                                   (((((oo)))))                                                   ((((o)(o))))                                                   (((o))((o)))                                                   ((((((o)))))) MATHEMATICA dallt[n_]:=Select[Union[Sort/@Join@@(Tuples[dallt/@#]&/@IntegerPartitions[n-1])], Intersection[Union@@Rest[FixedPointList[Union@@#&, #]], #]=={}&]; Table[Length[dallt[n]], {n, 10}] CROSSREFS Cf. A000081, A279861, A290689, A304360, A306844, A318185. Cf. A324695, A324751, A324756, A324758, A324763, A324765, A324768, A324769, A324770. Cf. A324838, A324841, A324844, A324846. Sequence in context: A097799 A005629 A028304 * A316475 A303875 A331037 Adjacent sequences:  A324837 A324838 A324839 * A324841 A324842 A324843 KEYWORD nonn,more AUTHOR Gus Wiseman, Mar 17 2019 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 28 11:31 EST 2020. Contains 332323 sequences. (Running on oeis4.)