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A071659
Permutation of natural numbers induced by the automorphism car_cdr_robr! acting on the parenthesizations encoded by A014486.
6
0, 1, 3, 2, 7, 8, 4, 6, 5, 17, 18, 20, 21, 22, 10, 9, 14, 16, 19, 11, 12, 15, 13, 45, 46, 48, 49, 50, 54, 55, 57, 58, 59, 61, 62, 63, 64, 26, 27, 23, 25, 24, 38, 37, 42, 44, 47, 51, 53, 56, 60, 29, 28, 30, 32, 31, 39, 40, 43, 52, 33, 34, 35, 41, 36, 129, 130, 132, 133, 134
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 (car_cdr_robr! s) (cond ((not (pair? s))) ((not (pair? (car s))) (swap! s)) (else (car_cdr_robr! (car s)) (car_cdr_robr! (cdr s)) (robr! 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: A071660. The car/cdr-flipped conjugate of A071656, i.e. A071659(n) = A057163(A071656(A057163(n))). Cf. also A071657, A071658.
Sequence in context: A069774 A089861 A072092 * A130931 A130962 A130367
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 30 2002
STATUS
approved