A375579 Lexicographically earliest sequence of distinct positive integers such that the products of two consecutive terms belong to A055932.

1, 2, 3, 4, 6, 5, 12, 8, 9, 10, 15, 14, 30, 7, 60, 16, 18, 20, 21, 40, 24, 25, 36, 27, 32, 45, 28, 75, 42, 35, 48, 50, 54, 64, 72, 70, 33, 140, 63, 80, 81, 90, 49, 120, 56, 105, 22, 210, 11, 420, 44, 315, 66, 175, 84, 55, 126, 100, 96, 108, 125, 144, 128, 135

Offset

1,2

Comments

a(n+1) is a multiple of A083720(a(n)).

This sequence has similarities with A175343; here we consider prime factors of consecutive terms, there ones in binary expansions of consecutive terms.

Links

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

Rémy Sigrist, PARI program

Example

The first terms, alongside their prime factors, are:
  n   a(n)  2  3  5  7
  --  ----  -  -  -  -
   1     1
   2     2  X
   3     3     X
   4     4  X
   5     6  X  X
   6     5        X
   7    12  X  X
   8     8  X
   9     9     X
  10    10  X     X
  11    15     X  X
  12    14  X        X

Prog

(PARI) \\ See Links section.

Crossrefs

Cf. A055932, A083720, A175343, A375281, A375615.

Sequence in context: A369137 A075160 A119755 * A206710 A175502 A364246

Adjacent sequences: A375576 A375577 A375578 * A375580 A375581 A375582

Keyword

nonn

Author

Rémy Sigrist, Aug 19 2024

Status

approved