|
Search: id:A153830
|
|
|
| A153830 |
|
Index sequence to A089840: positions of bijections that preserve A127302 (the non-oriented form of binary trees) and whose behaviour does not depend on whether there are internal or terminal nodes (leaves) in the neighbourhood of any vertex. |
|
+0
8
|
|
| 0, 1, 3, 7, 15, 21, 27, 46, 92, 114, 149, 169, 225, 251, 299, 400, 638, 753, 1233, 1348, 1705, 1823, 1992, 2097, 2335, 2451, 2995, 3128, 3485, 3607, 3677, 3771, 4214, 4307, 4631, 5254, 6692, 7393, 10287, 10988, 13145, 13860, 20353, 21054
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
COMMENT
|
These elements form a subgroup in A089840 (A089839) isomorphic to a group consisting of all finitely iterated wreath products of the form S_2 wr S_2 wr ... wr S_2 and each is an image of some finitary automorphism of an infinite binary tree. E.g. A089840(1) = *A069770 is an image of the generator A of Grigorchuk Group. See comments at A153246 and A153141.
The definining properties are propagated by all recursive transformations of A089840 which themselves do not behave differently depending whether there are internal or terminal vertices in the neighbourhood of any vertex (at least the ones given in A122201-A122204, A122283-A122290, A130400-A130403), so this sequence gives also the corresponding positions in those tables.
|
|
LINKS
|
A. Karttunen, Table of n, a(n) for n = 0..175
A. Karttunen, C-program for computing the initial terms of this sequence
|
|
CROSSREFS
|
Subset of A153829. Cf. also A153831, A153826, A153827, A153828, A153832, A153833.
Sequence in context: A138847 A077777 A153829 this_sequence A080550 A043725 A121712
Adjacent sequences: A153827 A153828 A153829 this_sequence A153831 A153832 A153833
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Antti Karttunen (His_Firstname.His_Surname(AT)gmail.com), Jan 07 2009
|
|
|
Search completed in 0.002 seconds
|
