A330623 Lexicographically earliest sequence of positive terms such that for any n > 0 and k > 0, a(n+2*k) <> gcd(a(n), a(n+k)).

1, 1, 2, 2, 3, 2, 2, 3, 3, 4, 4, 2, 4, 3, 3, 5, 3, 3, 4, 4, 5, 4, 4, 2, 5, 6, 2, 5, 6, 3, 6, 4, 3, 6, 6, 5, 4, 4, 3, 4, 5, 5, 6, 7, 5, 4, 4, 6, 4, 4, 7, 5, 5, 6, 5, 6, 7, 8, 4, 5, 7, 7, 6, 7, 8, 6, 3, 6, 7, 8, 5, 5, 8, 3, 6, 9, 5, 8, 7, 5, 9, 7, 7, 8, 6, 5, 8

Offset

1,3

Comments

This sequence differs radically from the variant where we consider nonnegative terms (A330622).

Links

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

Rémy Sigrist, Scatterplot of the first 250000 terms

Rémy Sigrist, C program for A330623

Prog

(C) See Links section.

Crossrefs

Cf. A330622 (nonnegative variant).

See A330267 for similar sequences.

Sequence in context: A187182 A362816 A176208 * A153095 A254574 A306991

Adjacent sequences: A330620 A330621 A330622 * A330624 A330625 A330626

Keyword

nonn

Author

Rémy Sigrist, Dec 21 2019

Status

approved