A168080 Numbers n such that exactly two of n+-1, n+-2 and n+-3 are primes.

0, 1, 2, 3, 9, 12, 15, 18, 21, 22, 26, 28, 30, 32, 34, 38, 39, 42, 45, 46, 50, 56, 58, 60, 62, 64, 68, 69, 72, 74, 76, 80, 81, 82, 86, 98, 99, 102, 105, 108, 111, 112, 128, 129, 130, 134, 136, 138, 140, 148, 150, 152, 154, 160, 164, 165, 166, 170, 176, 178, 180, 182

Offset

1,3

Links

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

Mathematica

okQ[n_]:=Length[Select[Drop[Range[n-3, n+3], {4}], PrimeQ]]==2; Join[{0, 1}, Select[Range[0, 200], okQ]] (* Harvey P. Dale, Jun 29 2011 *)

Crossrefs

Cf. A000040, A100317.

Sequence in context: A088086 A088084 A182203 * A048084 A350439 A067719

Adjacent sequences: A168077 A168078 A168079 * A168081 A168082 A168083

Keyword

nonn

Author

Juri-Stepan Gerasimov, Nov 18 2009

Extensions

Corrected (14 removed, 58, 62, 74 inserted, etc.) by R. J. Mathar, Jun 04 2010

Status

approved