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 A067026 (Prime(n)# - 4)/2 is prime, where x# is the primorial A034386(x). 24
 3, 4, 5, 6, 7, 8, 9, 11, 13, 16, 20, 27, 39, 83, 103, 122, 129, 145, 279, 393, 608, 798, 929, 1164, 1266, 1491, 2043, 3276, 3426, 7119, 15711, 18424 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS n such that A002110(n)/2 - 2 is prime. a(33) > 25000. - Robert Price, Sep 29 2017 LINKS MATHEMATICA p = 1; Do[p = p*Prime[n]; If[PrimeQ[(p - 4)/2], Print[n]], {n, 1, 400} ] Flatten[Position[Rest[FoldList[Times, 1, Prime[Range[2100]]]], _?(PrimeQ[(#-4)/2]&)]] (* Harvey P. Dale, Nov 22 2014 *) CROSSREFS Cf. A002110, A067024, A067027. Sequence in context: A189080 A039113 A130399 * A096829 A265126 A039120 Adjacent sequences:  A067023 A067024 A067025 * A067027 A067028 A067029 KEYWORD nonn AUTHOR Labos Elemer, Dec 29 2001 EXTENSIONS More terms from Robert G. Wilson v, Dec 30 2001 a(21)-a(27) from Ray Chandler, Jun 16 2013 a(28)-a(32) from Robert Price, Sep 29 2017 STATUS approved

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Last modified October 23 17:32 EDT 2019. Contains 328373 sequences. (Running on oeis4.)