A174153 Numbers k such that 2*13^k - 1 is prime.

2, 8, 10, 64, 76, 118, 120, 258, 303, 332, 364, 528, 811, 1270, 1362, 1607, 2091, 2572, 3596, 8190, 34271, 37860, 37938

Offset: 1

Author

Vincenzo Librandi, Mar 10 2010

Keywords

• nonn
• more

Comments

a(21) > 14400. - Jinyuan Wang, Feb 26 2020

Programs

Magma

/* The code gives only the terms up to 1607: */ [n: n in [0..1700] | IsPrime(2*13^n-1)];

Mathematica

Select[Range[5000], PrimeQ[(2 13^# - 1)] &] (* Vincenzo Librandi, Oct 05 2012 *)

PARI

is(n)=ispseudoprime(2*13^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(14)-a(19) from Vincenzo Librandi, Oct 05 2012

a(20) from Jinyuan Wang, Feb 26 2020

a(21)-a(23) from Michael S. Branicky, Jul 07 2024