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%I #5 Apr 30 2014 01:53:47
%S 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,
%T 51,52,54,60,62,37,38,61,39,40,41,57,56,63,42,43,58,44,45,23,24,46,25,
%U 26,27,59,47,48,28,29,49,30,31,32,50,33,34,35,36,162,191,192,154,155
%N Permutation of natural numbers induced by the automorphism cdr_robl_car! 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 source 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 (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)
%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: A071657 and also its car/cdr-flipped conjugate, i.e. A071658(n) = A057163(A071657(A057163(n))). Cf. also A071655, A071656, A071659, A071660.
%K nonn
%O 0,3
%A _Antti Karttunen_, May 30 2002