A137653 Numbers k such that 12^k + 7 is prime.

1, 2, 4, 5, 6, 20, 21, 22, 28, 58, 120, 144, 1100, 1926, 2892, 4773, 5214, 17241, 18980

Offset

1,2

Comments

a(18) > 7150. - Jinyuan Wang, Mar 03 2020

Links

Table of n, a(n) for n=1..19.

Mathematica

Do[If[PrimeQ[(12^n+7)], Print[n]], {n, 2000}]

Prog

(PARI) is(n)=ispseudoprime(12^n+7) \\ Charles R Greathouse IV, Jun 06 2017

Crossrefs

Cf. A137652, A137654.

Sequence in context: A008319 A033311 A098504 * A021411 A257433 A005532

Adjacent sequences: A137650 A137651 A137652 * A137654 A137655 A137656

Keyword

nonn,more

Author

Zak Seidov, Feb 01 2008

Extensions

a(15)-a(17) from Jinyuan Wang, Mar 03 2020

a(18)-a(19) from Michael S. Branicky, Mar 15 2023

Status

approved