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 A375497 #13 Aug 28 2024 11:27:40 %S A375497 1,2,3,6,7,8,10,11,15,17,18,20,21,26,27,28,29,30,33,36,39,42,43,44,45, %T A375497 46,47,48,51,52,53,54,55,56,57,64,65,69,70,71,72,75,78,79,80,81,82,83, %U A375497 89,90,92,93,96,97,98,99,100,101,102,105,106,107,108,110,111,114,115,117,118,119,120 %N A375497 Numbers k such that 16*k^4 - 1 is squarefree. %p A375497 select(k -> numtheory:-issqrfree(16*k^4-1), [$1..200]); # _Robert Israel_, Aug 18 2024 %t A375497 Select[Range[120], SquareFreeQ[16 * #^4 - 1] &] (* _Amiram Eldar_, Aug 18 2024 *) %o A375497 (Magma) [k: k in [1..120] | IsSquarefree(16*k^4-1)]; %o A375497 (PARI) isok(k) = issquarefree(16*k^4 - 1); \\ _Michel Marcus_, Aug 18 2024 %Y A375497 Cf. A005117, A016744. %K A375497 nonn %O A375497 1,2 %A A375497 _Juri-Stepan Gerasimov_, Aug 18 2024