A336200 Lexicographically earliest sequence of distinct terms such that every integer k appears twice, at distance a(k).

1, 1, 2, 2, 3, 4, 3, 4, 5, 6, 8, 5, 7, 6, 8, 7, 9, 10, 11, 12, 13, 9, 14, 10, 12, 15, 11, 13, 14, 16, 17, 18, 19, 15, 20, 21, 16, 23, 22, 17, 24, 18, 25, 19, 26, 27, 20, 22, 21, 28, 24, 23, 29, 30, 25, 31, 27, 32, 33, 26, 35, 34, 28, 36, 38, 37, 29, 39, 40, 30

Offset

1,3

Comments

This sequence combines features of A001462 and of A026242.

Links

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

Rémy Sigrist, PARI program for A336200

Example

For n = 1:
- we can choose a(1) = 1,
- and then a(1+a(1)) = a(2) = 1.
For n = 3:
- we can choose a(3) = 2,
- and then a(3+a(2)) = a(4) = 2.
For n = 5:
- we can choose a(5) = 3,
- and then a(5+a(3)) = a(7) = 3.

Prog

(PARI) See Links section.

Crossrefs

Cf. A001462, A026242.

Sequence in context: A162619 A259196 A357589 * A032355 A308597 A205153

Adjacent sequences: A336197 A336198 A336199 * A336201 A336202 A336203

Keyword

nonn

Author

Rémy Sigrist, Jul 11 2020

Status

approved