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, 31265
Offset: 1
Programs
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Mathematica
Do[If[PrimeQ[(12^n+7)],Print[n]],{n,2000}] -
PARI
is(n)=ispseudoprime(12^n+7) \\ Charles R Greathouse IV, Jun 06 2017
Extensions
a(15)-a(17) from Jinyuan Wang, Mar 03 2020
a(18)-a(19) from Michael S. Branicky, Mar 15 2023
a(20) from Michael S. Branicky, Jul 28 2024