login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A129606 Signature-permutation of a Catalan automorphism, row 3613 of A089840. 3
0, 1, 2, 3, 4, 6, 5, 7, 8, 9, 14, 10, 16, 19, 11, 15, 12, 17, 18, 13, 20, 21, 22, 23, 24, 37, 42, 51, 25, 38, 26, 44, 47, 27, 53, 56, 60, 28, 39, 29, 43, 52, 30, 40, 31, 45, 46, 32, 48, 49, 50, 33, 41, 34, 54, 55, 35, 57, 58, 59, 36, 61, 62, 63, 64, 65, 66, 67, 68, 69, 107 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
This involution effects the following transformation on the binary trees (labels A,B,C,D refer to arbitrary subtrees located on those nodes and () stands for a terminal node.)
.....C...D.........B...D
......\./...........\./
...B...X2........A...Y2......B..().......A..()
....\./...........\./.........\./.........\./
.A...X1....-->.C...Y1......A...X1..-->.B...Y1
..\./...........\./.........\./.........\./
...X0............Y0..........X0..........Y0
Note that automorphism *A072796 = ENIPS(*A129606). See the definition given in A122204.
LINKS
PROG
(Constructive and destructive Scheme implementation of this automorphism. These act on S-expressions, i.e. list-structures:)
(define (*A129606 s) (cond ((> (length s) 2) (cons (caddr s) (cons (car s) (cons (cadr s) (cdddr s))))) (else (*A072796 s))))
(define (*A129606! s) (cond ((< (length s) 3) (*A072796! s)) (else (let ((org_car (car s))) (set-car! s (caddr s)) (set-car! (cddr s) (cadr s)) (set-car! (cdr s) org_car) s))))
CROSSREFS
Inverse: A129605.
Sequence in context: A364824 A062894 A339723 * A057510 A130920 A127285
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 22 2007
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 04:59 EDT 2024. Contains 371264 sequences. (Running on oeis4.)