A079877 Numbers n that are divisible by at least one twin prime (A001097), and furthermore, if a twin prime p divides n, then the other twin q also divides n.

15, 30, 35, 45, 60, 70, 75, 90, 105, 120, 135, 140, 143, 150, 165, 175, 180, 195, 210, 225, 240, 245, 255, 270, 280, 285, 286, 300, 315, 323, 330, 345, 350, 360, 375, 385, 390, 405, 420, 429, 435, 450, 455, 465, 480, 490, 495, 510, 525, 540, 555, 560, 570

Offset

1,1

Comments

Numbers that are divisible by both primes of some twin-prime pair. Harvey P. Dale, Aug 18 2017

By definition, if k is in the sequence, then so is every positive multiple of k. - Richard Locke Peterson, Aug 17 2017

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

429 = 3*11*13 = 3*A001359(3)*A006512(3), therefore 429 is a term.

Mathematica

Select[Range[600], MemberQ[Differences[Transpose[FactorInteger[#]][[1]]], 2]&] (* Harvey P. Dale, Sep 19 2011 *)

Crossrefs

Cf. A001097, A001359, A006512, A037074, A062505, A074480, A289484.

Sequence in context: A162592 A239247 A291045 * A215951 A060700 A167210

Adjacent sequences: A079874 A079875 A079876 * A079878 A079879 A079880

Keyword

nonn

Author

Reinhard Zumkeller, Feb 20 2003

Extensions

Definition clarified by N. J. A. Sloane, Aug 18 2017

Status

approved