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A307664
Lexicographically earliest sequence of positive terms, such that each value, say v, appears three times at indices k, k + v and k + 2*v for some k.
3
1, 1, 1, 2, 4, 2, 5, 2, 4, 6, 7, 5, 4, 9, 11, 6, 5, 7, 8, 10, 12, 6, 9, 14, 7, 11, 8, 3, 13, 10, 3, 9, 12, 3, 8, 15, 11, 14, 17, 10, 18, 13, 19, 16, 12, 21, 22, 23, 25, 20, 15, 14, 26, 24, 13, 17, 27, 28, 18, 16, 31, 19, 32, 29, 33, 15, 21, 35, 22, 20, 23, 34
OFFSET
1,4
COMMENTS
This sequence is a variant of A026242 where each value, say v, appears twice at indices k and k + v for some k.
Graphically, we have three lines.
Apparently every positive integer appears in the sequence.
LINKS
EXAMPLE
For n = 1:
- we can set a(1) = a(2) = a(3) = 1.
For n = 4:
- we can set a(4) = a(6) = a(8) = 2.
For n = 5:
- a(8) is already known, hence a(5) <> 3,
- we can set a(5) = a(9) = a(13) = 4.
PROG
(PARI) See Links section.
CROSSREFS
See A307667 and A307669 for other variants.
Cf. A026242.
Sequence in context: A347184 A019294 A238262 * A057037 A076920 A183225
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Apr 20 2019
STATUS
approved