cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A065252 The sequence A065251 reduced modulo 3 (i.e., replace every -1 with 2).

Original entry on oeis.org

1, 1, 0, 1, 0, 2, 1, 1, 0, 2, 1, 0, 2, 1, 0, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2, 1, 0, 2
Offset: 1

Views

Author

Antti Karttunen, Oct 25 2001

Keywords

Programs

  • Maple
    [seq((A065251(j) mod 3),j=1..120)];

Formula

a(0)=0, a(2n) = 2 - a(n), a(2n+1) = 2 - ((a(n)+1) mod 3).

A120705 Permutation of natural numbers induced by the Catalan bijection gma120705 acting on the binary trees encoded by A014486/A063171.

Original entry on oeis.org

0, 1, 3, 2, 8, 7, 4, 5, 6, 22, 21, 17, 18, 20, 10, 9, 11, 13, 12, 14, 15, 19, 16, 64, 63, 58, 59, 62, 46, 45, 48, 50, 49, 54, 55, 61, 57, 27, 26, 23, 24, 25, 29, 28, 33, 34, 35, 30, 36, 32, 31, 38, 37, 39, 41, 40, 51, 52, 60, 56, 42, 43, 44, 47, 53, 196, 195, 189, 190, 194
Offset: 0

Views

Author

Antti Karttunen, Jun 28 2006

Keywords

Comments

When the automorphisms A120705/A120705 act on the full Stern-Brocot tree (A007305/A047679), which is an infinite binary tree, they will move each fraction r to the position of 2*r (or r/2 respectively). See comments at A065249 and A065251. (Proof in preparation, to be published.)

Crossrefs

Inverse of A120706. Cf. A074680.
Number of cycles: A120707. Number of fixed-points: A019590. Max. cycle size: A120708. LCM of cycle sizes: A120709.

A065249 Permutation of N induced by the order-preserving permutation of the positive rational numbers (x -> x/2), positions in Stern-Brocot tree.

Original entry on oeis.org

2, 8, 1, 32, 4, 11, 6, 128, 16, 35, 18, 5, 47, 24, 3, 512, 64, 131, 66, 17, 143, 72, 9, 21, 44, 23, 191, 96, 12, 27, 14, 2048, 256, 515, 258, 65, 527, 264, 33, 69, 140, 71, 575, 288, 36, 75, 38, 10, 87, 176, 22, 93, 188, 95, 767, 384, 48, 99, 50, 13, 111, 56, 7, 8192
Offset: 1

Views

Author

Antti Karttunen, Oct 25 2001

Keywords

Crossrefs

Cf. A057114, A065251. Inverse permutation: A065250.

Programs

  • Maple
    [seq(A065249(j),j=1..120)]; A065249 := n -> frac2position_in_whole_SB_tree((SternBrocotTreeNum(n)/SternBrocotTreeDen(n))/2);

A065250 Permutation of N induced by the order-preserving permutation of the positive rational numbers (x -> 2x), positions in Stern-Brocot tree.

Original entry on oeis.org

3, 1, 15, 5, 12, 7, 63, 2, 23, 48, 6, 29, 60, 31, 255, 9, 20, 11, 95, 192, 24, 51, 26, 14, 119, 240, 30, 125, 252, 127, 1023, 4, 39, 80, 10, 45, 92, 47, 383, 768, 96, 195, 98, 25, 207, 104, 13, 57, 116, 59, 479, 960, 120, 243, 122, 62, 503, 1008, 126, 509, 1020, 511
Offset: 1

Views

Author

Antti Karttunen, Oct 25 2001

Keywords

Crossrefs

Cf. A057114, A065251. Inverse permutation A065249.

Programs

  • Maple
    [seq(A065250(j),j=1..120)]; A065250 := n -> frac2position_in_whole_SB_tree((SternBrocotTreeNum(n)/SternBrocotTreeDen(n))*2);
Showing 1-4 of 4 results.