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A217385 Numbers n such that 9^n + 8 is prime. 1
1, 2, 4, 7, 10, 19, 22, 44, 62, 76, 122, 2191, 3134, 9244, 40999, 48230 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Contains exactly the halved even terms of A217136. - Bruno Berselli, Oct 04 2012

LINKS

Table of n, a(n) for n=1..16.

MATHEMATICA

Select[Range[5000], PrimeQ[9^# + 8] &]

PROG

(PARI) is(n)=ispseudoprime(9^n+8) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A090649, A177093, A217136, A217384.

Sequence in context: A274352 A343328 A088762 * A138827 A173730 A036685

Adjacent sequences:  A217382 A217383 A217384 * A217386 A217387 A217388

KEYWORD

nonn,hard,more

AUTHOR

Vincenzo Librandi, Oct 04 2012

EXTENSIONS

a(14) from Bruno Berselli, Oct 05 2012

a(15)-a(16) derived from A217136 by Robert Price, May 19 2015

STATUS

approved

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Last modified October 19 16:25 EDT 2021. Contains 348091 sequences. (Running on oeis4.)