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A168063
Numbers k such that exactly two of {k-2, k-1, k+1, k+2} are primes.
2
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
OFFSET
1,2
COMMENTS
Essentially the same as A014574 U A087679. - Charles R Greathouse IV, May 25 2011
LINKS
MATHEMATICA
Select[Range[700], Count[#+{-2, -1, 1, 2}, _?PrimeQ]==2&] (* Harvey P. Dale, Jan 24 2014 *)
CROSSREFS
Sequence in context: A192577 A236343 A325420 * A039873 A096394 A075472
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Corrected (105 inserted, 609 removed) by R. J. Mathar, Jun 04 2010
STATUS
approved