A069773 Permutation of natural numbers induced by the automorphism RoblDownCar_et_Swap! acting on the parenthesizations encoded by A014486.

0, 1, 3, 2, 6, 8, 7, 4, 5, 14, 15, 19, 20, 22, 16, 21, 17, 9, 10, 18, 11, 12, 13, 37, 38, 39, 40, 41, 51, 52, 53, 54, 55, 60, 61, 62, 64, 42, 43, 56, 57, 63, 44, 58, 45, 23, 24, 46, 25, 26, 27, 47, 59, 48, 28, 29, 49, 30, 31, 32, 50, 33, 34, 35, 36, 107, 108, 109, 110, 111

Offset

0,3

Links

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

Prog

(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))

Crossrefs

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

Keyword

nonn

Author

Antti Karttunen, Apr 16 2002

Status

approved