A352846 a(n) is the greatest k < n such that A109812(k) AND A109812(n) = A109812(k) or 0 if no such k exists (where AND denotes the bitwise AND operator).

0, 0, 0, 2, 0, 3, 5, 0, 3, 5, 8, 5, 8, 12, 0, 9, 8, 15, 8, 10, 15, 13, 15, 19, 15, 12, 15, 26, 0, 19, 23, 29, 17, 25, 29, 17, 21, 29, 30, 29, 36, 29, 25, 19, 35, 23, 29, 43, 47, 0, 44, 40, 50, 44, 40, 50, 46, 47, 50, 25, 42, 27, 38, 27, 38, 27, 42, 27, 67, 50

Offset

1,4

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, Scatterplot of the first 500000 terms

Rémy Sigrist, C++ program

Formula

a(n) = 0 iff A109812(n) is a power of 2.

Example

For k = 9:
- A109812(9) = 6,
- also:
      k  A109812(k)  A109812(7) AND A109812(k)
      -  ----------  -------------------------
      8          16                          0
      7          10                          2
      6           5                          4
      5           8                          0
      4           3                          2
      3           4                          4 <- A109812(3)
- so a(9) = 3.

Prog

(C++) See Links section.

Crossrefs

Cf. A109812, A352845.

Sequence in context: A321171 A336973 A369017 * A035347 A094126 A293269

Adjacent sequences: A352843 A352844 A352845 * A352847 A352848 A352849

Keyword

nonn,base

Author

Rémy Sigrist, Apr 05 2022

Status

approved