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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).
4
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
1,2
COMMENTS
This sequence is a variant of A329544.
LINKS
EXAMPLE
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
PROG
(PARI) See Links section.
CROSSREFS
See A330402 and A330403 for similar sequences.
Cf. A002113, A329544, A330420 (running totals).
Sequence in context: A262374 A299442 A299440 * A145518 A256221 A359099
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Dec 13 2019
STATUS
approved