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A056800
Numbers n such that 6*9^n +1 is prime.
1
0, 2, 4, 8, 28, 32, 448, 2108, 3112, 76264
OFFSET
1,2
COMMENTS
a(11) > 10^5. - Robert Price, Jun 04 2015
MATHEMATICA
Do[If[PrimeQ[6*9^n + 1], Print[n]], {n, 0, 1000}]
Select[Range[3000], PrimeQ[6 9^# + 1] &] (* Vincenzo Librandi, Sep 28 2012 *)
PROG
(PARI) is(n)=ispseudoprime(6*9^n+1) \\ Charles R Greathouse IV, Jun 12 2017
CROSSREFS
Sequence in context: A006399 A326293 A324328 * A302915 A259135 A219969
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Aug 22 2000
EXTENSIONS
a(8) from Vincenzo Librandi, Sep 28 2012
a(9)-a(10) from Robert Price, Jun 04 2015
STATUS
approved