0,3

Table of n, a(n) for n=0..69.

A. Karttunen, Gatomorphisms (Includes the complete Scheme program for computing this sequence)

Index entries for sequences that are permutations of the natural numbers

(Scheme function implementing this automorphism on list-structures:) (define (RoblDownCar_et_SwapInv! s) (cond ((not (pair? s))) ((not (pair? (car s))) (swap! s)) (else (RoblDownCar_et_SwapInv! (car 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))

Inverse of A069773, the car/cdr-flipped conjugate of A057502, i.e. A069774(n) = A057163(A057502(A057163(n))). Cf. also A069776.

Sequence in context: A074688 A130998 A130926 * A089861 A072092 A071659

Adjacent sequences: A069771 A069772 A069773 * A069775 A069776 A069777

nonn

Antti Karttunen, Apr 16 2002

approved