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A168080 Numbers n such that exactly two of n+-1, n+-2 and n+-3 are primes. 1
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 (list; graph; refs; listen; history; text; internal format)
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 A067719 A057017

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

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Last modified September 26 17:30 EDT 2021. Contains 347670 sequences. (Running on oeis4.)