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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, 586240 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The even members of A005538, halved. - Jeppe Stig Nielsen, Oct 13 2019

LINKS

Table of n, a(n) for n=1..17.

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,more,changed

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

a(17) from Paul S. Vanderveen, Jul 04 2020

STATUS

approved

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Last modified July 10 00:25 EDT 2020. Contains 335570 sequences. (Running on oeis4.)