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.

A352909 Pairs (i,j) of nonnegative integers with disjoint binary expansions sorted first by i+j then by i.

Original entry on oeis.org

0, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 3, 1, 2, 2, 1, 3, 0, 0, 4, 4, 0, 0, 5, 1, 4, 4, 1, 5, 0, 0, 6, 2, 4, 4, 2, 6, 0, 0, 7, 1, 6, 2, 5, 3, 4, 4, 3, 5, 2, 6, 1, 7, 0, 0, 8, 8, 0, 0, 9, 1, 8, 8, 1, 9, 0, 0, 10, 2, 8, 8, 2, 10, 0, 0, 11, 1, 10, 2, 9, 3, 8, 8, 3, 9, 2, 10, 1, 11, 0, 0, 12, 4, 8, 8, 4, 12, 0, 0, 13, 1, 12, 4, 9, 5, 8, 8, 5, 9, 4, 12, 1, 13, 0
Offset: 1

Views

Author

N. J. A. Sloane, Apr 09 2022

Keywords

Comments

Pairs (i,j) with AND(i,j) = 0.
Allan C. Wechsler points out that when these points are plotted on a two-dimensional grid they form a rotated version of the Sierpinski Gasket (A047999).

Examples

			The first few pairs are [0, 0], [0, 1], [1, 0], [0, 2], [2, 0], [0, 3], [1, 2], [2, 1], [3, 0], [0, 4], [4, 0], [0, 5], [1, 4], [4, 1], [5, 0], [0, 6], [2, 4], [4, 2], [6, 0], [0, 7], [1, 6], [2, 5], [3, 4], [4, 3], [5, 2], [6, 1], [7, 0], ...
		

Crossrefs

Cf. A047999, A295989 (i values), A352910 (j values).

Programs

  • Maple
    with(Bits);
    M:=16; Nlis:=[];
    for s from 0 to M do for i from 0 to s do j:=s-i;
    if And(i,j)=0 then Nlis:=[op(Nlis),[i,j]]; fi;
    od: od:
    Nlis;
  • Mathematica
    A352909list[ij_] := Select[Array[{#, ij-#} &, ij+1, 0], BitAnd @@ # == 0 &];
    Flatten[Array[A352909list, 15, 0]] (* Paolo Xausa, Feb 24 2024 *)