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Numbers k such that 14^k + 3 is prime.
1

%I #20 Apr 08 2021 07:19:20

%S 1,2,9,24,42,74,221,620,14064,36697,152048,384558

%N Numbers k such that 14^k + 3 is prime.

%e 1 is a term since 14^1 + 3 = 17 is a prime.

%t Do[ If[ PrimeQ[ 14^n + 3], Print[n]], {n, 0, 200000}]

%o (PARI) is(n)=isprime(14^n + 3)

%Y Cf. A339924.

%K nonn,more

%O 1,2

%A _Paul Bourdelais_, Dec 23 2020

%E a(12) corresponds to a probable prime discovered by _Paul Bourdelais_, Jan 06 2021