A071655 Permutation of natural numbers induced by the automorphism robr_car_cdr! acting on the parenthesizations encoded by A014486.

0, 1, 3, 2, 7, 8, 5, 4, 6, 17, 18, 20, 21, 22, 12, 13, 10, 9, 11, 15, 14, 19, 16, 45, 46, 48, 49, 50, 54, 55, 57, 58, 59, 61, 62, 63, 64, 31, 32, 34, 35, 36, 26, 27, 24, 23, 25, 29, 28, 33, 30, 40, 41, 38, 37, 39, 52, 51, 56, 60, 43, 42, 47, 44, 53, 129, 130, 132, 133, 134

Offset

0,3

Links

Table of n, a(n) for n=0..69.

A. Karttunen, Gatomorphisms (Includes the complete Scheme source for computing this sequence)

Index entries for sequences that are permutations of the natural numbers

Prog

(Scheme function implementing this automorphism on list-structures:)
(define (robr_car_cdr! s) (cond ((not (pair? s))) ((not (pair? (car s))) (swap! s)) (else (robr! s) (robr_car_cdr! (car s)) (robr_car_cdr! (cdr s)))) s)
(define (robr! s) (let ((ex-cdr (cdr s))) (set-cdr! s (caar s)) (set-car! (car s) ex-cdr) (swap! (car s)) (swap! s) s))
(define (swap! s) (let ((ex-car (car s))) (set-car! s (cdr s)) (set-cdr! s ex-car) s))

Crossrefs

Inverse permutation: A071656. The car/cdr-flipped conjugate of A071660, i.e. A071655(n) = A057163(A071660(A057163(n))). Cf. also A071657, A071658.

Sequence in context: A129610 A130923 A057501 * A130964 A130929 A073270

Adjacent sequences: A071652 A071653 A071654 * A071656 A071657 A071658

Keyword

nonn

Author

Antti Karttunen, May 30 2002

Status

approved