A168063 - OEIS

A168063

Numbers k such that exactly two of {k-2, k-1, k+1, k+2} are primes.

1, 3, 5, 6, 9, 12, 15, 18, 21, 30, 39, 42, 45, 60, 69, 72, 81, 99, 102, 105, 108, 111, 129, 138, 150, 165, 180, 192, 195, 198, 225, 228, 231, 240, 270, 279, 282, 309, 312, 315, 348, 351, 381, 399, 420, 432, 441, 459, 462, 465, 489, 501, 522, 570, 600, 615, 618

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Essentially the same as A014574 U A087679. - Charles R Greathouse IV, May 25 2011

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[700], Count[#+{-2, -1, 1, 2}, _?PrimeQ]==2&] (* Harvey P. Dale, Jan 24 2014 *)

CROSSREFS

Cf. A014574, A087679.

Sequence in context: A192577 A236343 A325420 * A039873 A096394 A075472