A394850 Lexicographically earliest sequence of distinct positive integers such that among any pair of consecutive terms, one is a recursive divisor of the other.

1, 2, 4, 12, 3, 6, 18, 9, 36, 144, 16, 48, 240, 5, 10, 20, 60, 15, 30, 90, 45, 180, 720, 80, 400, 25, 50, 100, 300, 75, 150, 450, 225, 900, 3600, 1200, 8400, 7, 14, 28, 84, 21, 42, 126, 63, 252, 1008, 112, 336, 1680, 35, 70, 140, 420, 105, 210, 630, 315, 1260

Offset

1,2

Comments

We use the definition of recursive divisor given in A282446.

Like A282291, the sequence exhibits large sections matching the beginning of the sequence up to some multiplicative factor (see illustration in Links sections).

Links

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

Rémy Sigrist, Logarithmic scatterplot of the first 400000 terms (the red section equals the blue section multiplied by 31)

Rémy Sigrist, Illustration of initial terms

Rémy Sigrist, PARI program

Formula

min(a(n), a(n+1)) = A287957(a(n), a(n+1)).

Example

See illustration of initial terms in Links section.

Prog

(PARI) \\ See Links section.

Crossrefs

See A282291 for a similar sequence.

Cf. A282446, A287957.

Sequence in context: A215795 A070314 A075554 * A365000 A294103 A137369

Adjacent sequences: A394847 A394848 A394849 * A394851 A394852 A394853

Keyword

nonn

Author

Rémy Sigrist, Apr 04 2026

Status

approved