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%I #5 May 01 2014 02:47:41
%S 0,1,3,2,6,7,8,4,5,15,14,16,17,18,19,20,22,9,10,21,11,12,13,39,40,41,
%T 37,38,43,42,44,45,46,47,48,49,50,52,51,53,54,55,60,61,62,23,24,63,25,
%U 26,27,56,57,64,28,29,58,30,31,32,59,33,34,35,36,113,112,114,115,116
%N Permutation of natural numbers induced by the automorphism car_robl_cdr! acting on the parenthesizations encoded by A014486.
%H A. Karttunen, <a href="http://www.iki.fi/~kartturi/matikka/Nekomorphisms/gatomorf.htm">Gatomorphisms</a> (Includes the complete Scheme program for computing this sequence)
%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%o (Scheme function implementing this automorphism on list-structures:)
%o (define (car_robl_cdr! s) (cond ((not (pair? s))) ((not (pair? (cdr s))) (swap! s)) (else (car_robl_cdr! (car s)) (robl! s) (car_robl_cdr! (cdr s)))) s)
%o (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))
%o (define (swap! s) (let ((ex-car (car s))) (set-car! s (cdr s)) (set-cdr! s ex-car) s))
%Y Inverse permutation: A072090 and also its car/cdr-flipped conjugate, i.e. A072091(n) = A057163(A072090(A057163(n))). Cf. also A071655-A071660, A072092-A072095.
%K nonn
%O 0,3
%A _Antti Karttunen_, Jun 25 2002