A071656 Permutation of natural numbers induced by the automorphism car_cdr_robl! acting on the parenthesizations encoded by A014486.

0, 1, 3, 2, 7, 6, 8, 4, 5, 17, 16, 18, 14, 15, 20, 19, 22, 9, 10, 21, 11, 12, 13, 45, 44, 46, 42, 43, 48, 47, 50, 37, 38, 49, 39, 40, 41, 54, 53, 55, 51, 52, 61, 60, 63, 23, 24, 62, 25, 26, 27, 57, 56, 64, 28, 29, 58, 30, 31, 32, 59, 33, 34, 35, 36, 129, 128, 130, 126, 127

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 (car_cdr_robl! s) (cond ((not (pair? s))) ((not (pair? (cdr s))) (swap! s)) (else (car_cdr_robl! (car s)) (car_cdr_robl! (cdr s)) (robl! s))) s)
(define (robl! s) (let ((ex-car (car s))) (set-car! s (cddr s)) (set-cdr! (cdr s) ex-car) (swap! (cdr 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: A071655. The car/cdr-flipped conjugate of A071659, i.e. A071656(n) = A057163(A071659(A057163(n))). Cf. also A071657, A071658.

Sequence in context: A126851 A082321 A057502 * A130963 A130930 A072095

Adjacent sequences: A071653 A071654 A071655 * A071657 A071658 A071659

Keyword

nonn

Author

Antti Karttunen, May 30 2002

Status

approved