id:A071655 - OEIS Search Results

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

+0
15

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 (list; graph; listen)

	OFFSET	`0,3`
	LINKS	`A. Karttunen, Gatomorphisms (Includes the complete Scheme source for computing this sequence)` `Index entries for sequences that are permutations of the natural numbers`
	PROGRAM	`(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.` `Adjacent sequences: A071652 A071653 A071654 this_sequence A071656 A071657 A071658` `Sequence in context: A129610 A130923 A057501 this_sequence A130964 A130929 A073270`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen May 30 2002`

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Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.

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