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 A066652 #8 Feb 22 2021 03:16:41 %S A066652 3,5,11,13,19,29,37,41,43,59,61,67,73,83,101,109,113,131,137,139,157, %T A066652 163,173,181,193,211,227,229,257,277,281,283,307,313,317,331,347,353, %U A066652 373,379,389,397,401,409,419,421,433,443,457 %N A066652 Primes of the form 2*s - 1, where s is a squarefree number (A005117). %H A066652 Amiram Eldar, <a href="/A066652/b066652.txt">Table of n, a(n) for n = 1..10000</a> %e A066652 a(10) = A000040(17) = 59 = 2*30-1 = 2*A005117(19)-1. %t A066652 Select[2 * Select[Range[200], SquareFreeQ] - 1, PrimeQ] (* _Amiram Eldar_, Feb 22 2021 *) %Y A066652 Cf. A005383, A066651, A066653. %K A066652 nonn %O A066652 1,1 %A A066652 _Reinhard Zumkeller_, Jan 10 2002