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 A071660 Permutation of natural numbers induced by the automorphism robl_car_cdr! acting on the parenthesizations encoded by A014486. 12
 0, 1, 3, 2, 6, 8, 7, 4, 5, 15, 14, 19, 20, 22, 16, 21, 17, 9, 10, 18, 11, 12, 13, 39, 41, 40, 37, 38, 52, 51, 53, 55, 54, 60, 61, 62, 64, 43, 42, 56, 57, 63, 44, 58, 45, 23, 24, 46, 25, 26, 27, 47, 59, 48, 28, 29, 49, 30, 31, 32, 50, 33, 34, 35, 36, 113, 112, 117, 118, 120 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS A. Karttunen, Gatomorphisms (Includes the complete Scheme source for computing this sequence) PROG (Scheme function implementing this automorphism on list-structures:) (define (robl_car_cdr! s) (cond ((not (pair? s))) ((not (pair? (cdr s))) (swap! s)) (else (robl! s) (robl_car_cdr! (car s)) (robl_car_cdr! (cdr 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: A071659. The car/cdr-flipped conjugate of A071655, i.e. A071660(n) = A057163(A071655(A057163(n))). Cf. also A071657, A071658. Sequence in context: A072093 A130925 A089858 * A130393 A130956 A131001 Adjacent sequences:  A071657 A071658 A071659 * A071661 A071662 A071663 KEYWORD nonn AUTHOR Antti Karttunen, May 30 2002 STATUS approved

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Last modified October 15 15:14 EDT 2019. Contains 328030 sequences. (Running on oeis4.)