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A071658
Permutation of natural numbers induced by the automorphism cdr_robl_car! acting on the parenthesizations encoded by A014486.
8
0, 1, 3, 2, 8, 6, 7, 4, 5, 20, 19, 22, 14, 15, 21, 16, 17, 9, 10, 18, 11, 12, 13, 64, 53, 55, 51, 52, 54, 60, 62, 37, 38, 61, 39, 40, 41, 57, 56, 63, 42, 43, 58, 44, 45, 23, 24, 46, 25, 26, 27, 59, 47, 48, 28, 29, 49, 30, 31, 32, 50, 33, 34, 35, 36, 162, 191, 192, 154, 155
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 (cdr_robl_car! s) (cond ((not (pair? s))) ((not (pair? (cdr s))) (swap! s)) (else (cdr_robl_car! (cdr s)) (robl! s) (cdr_robl_car! (car 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: A071657 and also its car/cdr-flipped conjugate, i.e. A071658(n) = A057163(A071657(A057163(n))). Cf. also A071655, A071656, A071659, A071660.
Sequence in context: A098163 A260323 A072112 * A089860 A130960 A130927
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 30 2002
STATUS
approved