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 A056799 Numbers n such that 8*9^n +1 is prime. 6
 1, 4, 5, 11, 26, 29, 38, 65, 166, 490, 641, 2300, 9440, 44741, 65296, 161930 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(17)>2*10^5. - Robert Price, Feb 22 2016 The even members of A005538, halved. - Jeppe Stig Nielsen, Oct 13 2019 LINKS MATHEMATICA Do[If[PrimeQ[8*9^n + 1], Print[n]], {n, 0, 1000}] Select[Range[3000], PrimeQ[8 9^# + 1] &] (* Vincenzo Librandi, Sep 28 2012 *) PROG (PARI) is(n)=ispseudoprime(8*9^n+1) \\ Charles R Greathouse IV, Mar 01 2017 CROSSREFS Cf. A005538. Sequence in context: A000769 A246495 A050831 * A216963 A259821 A109503 Adjacent sequences:  A056796 A056797 A056798 * A056800 A056801 A056802 KEYWORD nonn AUTHOR Robert G. Wilson v, Aug 22 2000 EXTENSIONS a(12) from Vincenzo Librandi, Sep 28 2012 a(13)-a(16) from Robert Price, Feb 22 2016 STATUS approved

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Last modified December 6 18:03 EST 2019. Contains 329809 sequences. (Running on oeis4.)