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 A217128 #7 Sep 08 2022 08:46:04 %S A217128 4,5,6,7,9,11,13,15,16,18,19,20,21,22,25,26,29,30,31,32,33,34,35,36, %T A217128 38,39,42,43,46,47,48,49,50,51,52,54,55,56,57,58,60,61,62,63,64,65,67, %U A217128 68,69,72,73,74,75,76,78,79,81,83,84,85,86,88,89,91,92,93,94,95,96,98,100 %N A217128 Numbers n such that (2n)^4 + 1 is not prime. %H A217128 Vincenzo Librandi, <a href="/A217128/b217128.txt">Table of n, a(n) for n = 1..1000</a> %t A217128 Select[Range[100], ! PrimeQ[(2 #)^4 + 1] &] %o A217128 (Magma) [n: n in [1..100] | not IsPrime((2*n)^4+1)]; %Y A217128 Cf. A000059, A037896. %K A217128 nonn,easy %O A217128 1,1 %A A217128 _Vincenzo Librandi_, Sep 27 2012