A379850 a(n) is the number of integers (positive or negative) v that appears in the set {A377091(k), k = 0..n} without -v appearing in it.

0, 1, 2, 1, 0, 1, 2, 3, 2, 1, 2, 3, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 6, 5, 4, 3, 2, 3, 4, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 7, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6

Offset

0,3

Comments

Does this sequence contain infinitely many zeros? If so, A377091 would contain every positive and negative integers.

Links

Rémy Sigrist, Table of n, a(n) for n = 0..10000

Rémy Sigrist, PARI program

Formula

|a(n+1) - a(n)| = 1.

Example

The first terms, alongside A377091(n) and the corresponding v's, are:
  n   a(n)  A377091(n)  v's
  --  ----  ----------  ------------
   0     0           0  {}
   1     1           1  {1}
   2     2           2  {1, 2}
   3     1          -2  {1}
   4     0          -1  {}
   5     1           3  {3}
   6     2           4  {3, 4}
   7     3           5  {3, 4, 5}
   8     2          -4  {3, 5}
   9     1          -3  {5}
  10     2           6  {5, 6}
  11     3           7  {5, 6, 7}
  12     4           8  {5, 6, 7, 8}
  13     3          -8  {5, 6, 7}
  14     2          -7  {5, 6}
  15     1          -6  {5}
  16     0          -5  {}

Prog

(PARI) \\ See Links section.

Crossrefs

Cf. A377091.

Sequence in context: A037834 A212496 A380268 * A348295 A362598 A179765

Adjacent sequences: A379847 A379848 A379849 * A379853 A379854 A379855

Keyword

nonn

Author

Rémy Sigrist, Jan 04 2025

Status

approved