This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A121978 #15 Aug 28 2025 16:57:58
%S A121978 1,11,12,14,20,27,29,30,40,65,71,85,87,89,97,104,115,147,155,175,181,
%T A121978 189,194,244,263,264,285,286,291,303,354,360,370,376,403,407,417,423,
%U A121978 429,433,448,479,492,493,520,570,582,588,596,617,627,629,644,654,661
%N A121978 Numbers k such that (2*k^2)^8 + 1 is prime.
%C A121978 Corresponding primes of the form (2*k^2)^8 + 1 are {257, 11763130845074473217, 47330370277129322497, 557556054479199010817, 167772160000000000000001, ...}.
%C A121978 There are consecutive twin pairs {a(n),a(n+1)} = {11,12}, {29,30}, {263,264},{285,286}, {492,493}, {833,834}, ...
%H A121978 G. C. Greubel, <a href="/A121978/b121978.txt">Table of n, a(n) for n = 1..5000</a>
%t A121978 Select[Range[1000],PrimeQ[(2*#1^2)^8+1]&]
%t A121978 Select[Range[1000],PrimeQ[256#^16+1]&] (* _Harvey P. Dale_, Nov 04 2020 *)
%o A121978 (PARI) is(n)=isprime((2*n^2)^8+1) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y A121978 Cf. A006314.
%K A121978 nonn,easy,changed
%O A121978 1,2
%A A121978 _Alexander Adamchuk_, Sep 10 2006