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_Swap! s) (cond ((not (pair? s))) ((not (pair? (cdr s))) (swap! s)) (else (robl! s) (RoblDownCar_et_Swap! (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))

Inverse of A069774, the car/cdr-flipped conjugate of A057501, i.e. A069773(n) = A057163(A057501(A057163(n))). Cf. also A069775.

Sequence in context: A292961 A019444 A195412 * A122321 A072093 A130925

Adjacent sequences: A069770 A069771 A069772 * A069774 A069775 A069776

nonn

Antti Karttunen, Apr 16 2002

approved