A330402 Lexicographically earliest sequence of distinct positive terms with an associate sequence t such that t(0) = 0, and for any n > 0, at least one of t(n-1) - a(n) or t(n-1) + a(n) is a prime number; in case t(n-1) - a(n) is a prime number, set t(n) = t(n-1) - a(n), otherwise set t(n) = t(n-1) + a(n).

2, 1, 4, 5, 3, 6, 8, 10, 11, 9, 12, 14, 16, 18, 24, 20, 22, 28, 30, 26, 32, 34, 38, 36, 42, 40, 46, 44, 50, 45, 15, 54, 48, 21, 17, 52, 56, 60, 62, 66, 58, 70, 64, 78, 68, 27, 29, 72, 74, 80, 82, 84, 76, 96, 86, 39, 35, 90, 98, 102, 88, 41, 51, 104, 94, 100

Offset

1,1

Comments

This sequence is a variant of A330401.

Links

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

Rémy Sigrist, PARI program for A330402

Example

The first terms, alongside t(n), are:
  n   a(n)  t(n)
  --  ----  ----
   0  N/A      0
   1     2     2
   2     1     3
   3     4     7
   4     5     2
   5     3     5
   6     6    11
   7     8     3
   8    10    13
   9    11     2
  10     9    11
  11    12    23
  12    14    37

Prog

(PARI) See Links section.

Crossrefs

Cf. A330401, A330421 (running totals).

Sequence in context: A144203 A354699 A239806 * A075302 A352520 A350313

Adjacent sequences: A330399 A330400 A330401 * A330403 A330404 A330405

Keyword

nonn

Author

Rémy Sigrist, Dec 13 2019

Status

approved