A057913 - OEIS

%I #28 Sep 08 2024 05:26:56

%S 1,2,3,4,5,6,7,8,14,16,19,22,24,27,29,32,38,54,57,60,76,94,132,139,

%T 175,187,208,230,379,384,632,1040,1188,1359,1553,1734,1768,1925,2492,

%U 3272,3537,3949,4647,5869,6473,7036,8550,9459,9784,15440,15507,15637,16400,42045

%N Numbers k such that 3*2^k + 5 is prime.

%C a(79) > 10^6 per Grantham and Granville link, Section 6. - _Michael S. Branicky_, Sep 07 2024

%H Jon Grantham, <a href="/A057913/b057913.txt">Table of n, a(n) for n = 1..78</a>

%H Jon Grantham and Andrew Granville, <a href="https://arxiv.org/abs/2307.07894">Fibonacci primes, primes of the form 2^n-k and beyond</a>, arXiv:2307.07894 [math.NT], 2023.

%t Do[ If[ PrimeQ[ 3*2^n + 5 ], Print[ n ] ], {n, 1, 3000} ]

%o (PARI) {for(n=0, 10^6, if(isprime(k=5+3*2^n), print1(n, ", ")))} /* _Joerg Arndt_, Apr 13 2012 */

%Y Cf. A057912 (3*2^k - 5 is prime).

%K nonn

%O 1,2

%A _Robert G. Wilson v_, Nov 16 2000

%E a(54) from _Jinyuan Wang_, Feb 02 2020