A217385 Numbers n such that 9^n + 8 is prime.

1, 2, 4, 7, 10, 19, 22, 44, 62, 76, 122, 2191, 3134, 9244, 40999, 48230

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 A353055 A173730

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