A121978 - OEIS

%I #11 Nov 04 2020 17:07:20

%S 1,11,12,14,20,27,29,30,40,65,71,85,87,89,97,104,115,147,155,175,181,

%T 189,194,244,263,264,285,286,291,303,354,360,370,376,403,407,417,423,

%U 429,433,448,479,492,493,520,570,582,588,596,617,627,629,644,654,661

%N Numbers n such that (2n^2)^8 + 1 is prime.

%C Corresponding primes of the form (2n^2)^8 + 1 are {257, 11763130845074473217, 47330370277129322497, 557556054479199010817, 167772160000000000000001, ...}.

%C There are consecutive twin pairs {a(n),a(n+1)} = {11,12}, {29,30}, {263,264},{285,286}, {492,493}, {833,834}, ...

%H G. C. Greubel, <a href="/A121978/b121978.txt">Table of n, a(n) for n = 1..5000</a>

%t Select[Range[1000],PrimeQ[(2*#1^2)^8+1]&]

%t Select[Range[1000],PrimeQ[256#^16+1]&] (* _Harvey P. Dale_, Nov 04 2020 *)

%o (PARI) is(n)=isprime((2*n^2)^8+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%Y Cf. A006314.

%K nonn,easy

%O 1,2

%A _Alexander Adamchuk_, Sep 10 2006