A330401 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 palindrome; in case t(n-1) - a(n) is a palindrome, set t(n) = t(n-1) - a(n), otherwise set t(n) = t(n-1) + a(n).

1, 2, 3, 4, 5, 6, 8, 7, 18, 11, 9, 20, 13, 24, 22, 10, 21, 14, 25, 26, 15, 16, 27, 28, 17, 19, 30, 29, 40, 33, 44, 46, 35, 36, 47, 48, 37, 38, 49, 50, 39, 41, 52, 51, 62, 45, 12, 32, 43, 23, 34, 54, 60, 31, 61, 71, 81, 63, 53, 42, 55, 57, 68, 66, 72, 70, 79

Offset: 1

Author

Rémy Sigrist, Dec 13 2019

Keywords

• nonn
• base

Comments

This sequence is a variant of A329544.

Examples

			The first terms, alongside t(n), are:
  n   a(n)  t(n)
  --  ----  ----
   0  N/A      0
   1     1     1
   2     2     3
   3     3     0
   4     4     4
   5     5     9
   6     6     3
   7     8    11
   8     7     4
   9    18    22
  10    11    11
  11     9     2
  12    20    22
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..10000
• Rémy Sigrist, PARI program for A330401

Crossrefs

See A330402 and A330403 for similar sequences.

Cf. A002113, A329544, A330420 (running totals).

Programs

PARI

See Links section.