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.

A065263 Infinite binary tree inspired permutation of N: 1 -> 3, 11ab..yz -> 11ab..yz1, 10ab..y0 -> 10ab..y, 10ab..y1 -> 11AB..Y0 (where 1AB..Y0 is the complement of 0ab..y1).

Original entry on oeis.org

3, 1, 7, 2, 6, 13, 15, 4, 14, 5, 12, 25, 27, 29, 31, 8, 30, 9, 28, 10, 26, 11, 24, 49, 51, 53, 55, 57, 59, 61, 63, 16, 62, 17, 60, 18, 58, 19, 56, 20, 54, 21, 52, 22, 50, 23, 48, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 32, 126, 33, 124
Offset: 1

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Author

Antti Karttunen, Oct 28 2001

Keywords

Comments

When an infinite planar binary tree is mapped breadth-first-wise from left to right (1 is at top, 2 is its left and 3 its right child, 4 is 2's left child, etc.) then this permutation induces such rearrangement of its nodes, that on the right side every node replaces its right child, on the left side the left children replace their parents and the right children are reflected to the right side, to be the left children of their new parents.

Crossrefs

A057114, A065269, A065275, A065281, A065287. Inverse: A065264, conjugated with A059893: A065265 and the inverse of that: A065266.

Programs

  • Maple
    RightChildInverted := proc(n) local k; if(1 = n) then RETURN(3); fi; k := floor_log_2(n)-1; if(3 = floor(n/(2^k))) then RETURN((2*n)+1); fi; if(0 = (n mod 2)) then RETURN(n/2); fi; RETURN(2^(k+1) + ((2^(k+2))-1) - n); end;