A217493 Numbers k such that 9^k - 10 is prime.

2, 3, 4, 9, 11, 18, 19, 27, 28, 46, 50, 53, 80, 155, 203, 280, 451, 4963, 6167, 9687, 10083, 31450

Offset: 1

Author

Vincenzo Librandi, Oct 05 2012

Keywords

• nonn
• more

Comments

Contains exactly the halved even terms of A217347.

Crossrefs

Cf. A217137, A217347.

Programs

Mathematica

Select[Range[5000], PrimeQ[9^# - 10] &]

PARI

is(n)=ispseudoprime(9^n-10) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(19)-a(22) added from the data at A217347 by Amiram Eldar, Jun 19 2022