A057115 Order-preserving permutation of the rational numbers (x -> x-1); positions in Stern-Brocot tree.

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

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: A328641 A208741 A335957 * A065276 A065288 A065264

Adjacent sequences: A057112 A057113 A057114 * A057116 A057117 A057118

Keyword

nonn

Author

Antti Karttunen, Aug 09 2000

Status

approved