login
This site is supported by donations to The OEIS Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A057115 Order-preserving permutation of the rational numbers (x -> x-1); positions in Stern-Brocot tree. 9
2, 4, 1, 8, 9, 5, 3, 16, 17, 18, 19, 10, 11, 6, 7, 32, 33, 34, 35, 36, 37, 38, 39, 20, 21, 22, 23, 12, 13, 14, 15, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 40, 41, 42, 43, 44, 45, 46, 47, 24, 25, 26, 27, 28, 29, 30, 31, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..86.

Index entries for sequences related to Stern's sequences

Index entries for sequences that are permutations of the natural numbers

FORMULA

a(n) = frac2position_in_whole_SB_tree(sbtree_perm_1_1_left(SternBrocotTreeNum(n)/SternBrocotTreeDen(n)))

MAPLE

sbtree_perm_1_1_left := x -> (`if`((x <= 0), x, (`if`((x < 1), (x/(1+x)), (`if`((x < 2), (1/(3-x)), (x-1)))))));

CROSSREFS

Inverse permutation: A057114.

When conjugated with A059893, one gets A065260, a valid siteswap permutation.

The first row of A065626, i.e. a(n) = RotateNodeLeft(1, n).

Sequence in context: A193034 A254179 A208741 * A065276 A065288 A065264

Adjacent sequences:  A057112 A057113 A057114 * A057116 A057117 A057118

KEYWORD

nonn

AUTHOR

Antti Karttunen, Aug 09 2000

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 19 16:10 EST 2019. Contains 319307 sequences. (Running on oeis4.)