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 A066653 #21 Jul 26 2022 16:04:08
%S A066653 2,3,6,15,21,30,51,69,114,141,174,210,231,285,309,321,330,411,429,510,
%T A066653 546,615,645,651,714,741,834,849,861,894,939,966,1041,1065,1119,1155,
%U A066653 1191,1329,1365,1401,1626,1686,1695,1731,1770
%N A066653 Squarefree numbers k such that the pair 2*k +- 1 is a twin prime pair.
%H A066653 Amiram Eldar, <a href="/A066653/b066653.txt">Table of n, a(n) for n = 1..10000</a>
%F A066653 a(n) = 3*A355846(n-1), for n >= 2. - _Wesley Ivan Hurt_, Jul 24 2022
%e A066653 2*a(6) +/- 1 = 2*30 +/- 1 = (59, 61) = (A000040(17), A000040(18)) = (A001359(7), A006512(7)) = (A066652(10), A066651(13)).
%t A066653 Select[Range[2000], SquareFreeQ[#] && And @@ PrimeQ[2# + {-1, 1}] &] (* _Amiram Eldar_, Dec 19 2019 *)
%o A066653 (Magma) [k:k in [1..2000]|IsSquarefree(k) and IsPrime(2*k-1) and IsPrime(2*k+1)]; // _Marius A. Burtea_, Dec 19 2019
%o A066653 (PARI) isok(k) = issquarefree(k) && isprime(2*k-1) && isprime(2*k+1); \\ _Michel Marcus_, Jul 25 2022
%Y A066653 Cf. A014574, A001359, A006512, A066651, A066652, A355846.
%K A066653 nonn
%O A066653 1,1
%A A066653 _Reinhard Zumkeller_, Jan 10 2002