A180201 Inverse permutation to A180200.

0, 1, 2, 3, 5, 4, 6, 7, 11, 10, 8, 9, 13, 12, 14, 15, 23, 22, 20, 21, 17, 16, 18, 19, 27, 26, 24, 25, 29, 28, 30, 31, 47, 46, 44, 45, 41, 40, 42, 43, 35, 34, 32, 33, 37, 36, 38, 39, 55, 54, 52, 53, 49, 48, 50, 51, 59, 58, 56, 57, 61, 60, 62, 63, 95, 94, 92, 93, 89, 88, 90, 91, 83

Offset

0,3

Comments

A180199(n) = a(a(n));

a(A180198(n)) = A180198(a(n)) = A180200(n);

a(A075427(n)) = A075427(n).

This permutation transforms the enumeration system of positive irreducible fractions A245325/A245326 into the enumeration system A007305/A047679 (Stern-Brocot), and enumeration system A071766/A229742 (HCS) into A162909/A162910 (Bird). - Yosu Yurramendi, Jun 09 2015

Links

Table of n, a(n) for n=0..72.

Index entries for sequences that are permutations of the natural numbers

Formula

a(n) = A258746(A233280(n)) = A233280(A117120(n)), n > 0. - Yosu Yurramendi, Apr 10 2017

a(0) = 0, a(1) = 1, for n > 0 a(2*n) = 2*a(n) + [n even], a(2*n + 1) = 2*a(n) + [n odd]. - Yosu Yurramendi, May 23 2020

Prog

(R)
#
maxn <- 63 # by choice
a <- 1
for(n in 1:maxn){
a[2*n  ] <- 2*a[n] + (n%%2 == 0)
a[2*n+1] <- 2*a[n] + (n%%2 != 0)}
a <- c(0, a)
# Yosu Yurramendi, May 23 2020

Crossrefs

Sequence in context: A153150 A069766 A081241 * A233277 A279339 A279349

Adjacent sequences: A180198 A180199 A180200 * A180202 A180203 A180204

Keyword

nonn

Author

Reinhard Zumkeller, Aug 15 2010

Status

approved