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 A279183 #22 Dec 15 2024 04:38:10
%S A279183 1,2,12,152,222,362,432,992,1517,2532,2567,8472,34732,44092,69312,
%T A279183 82752,105852,114392,128672,336992,350082,393132,393552,462747,497712,
%U A279183 559872,665817,714502,931432,968952,1126602,1281867,1389337,1449992,1638712,1694292
%N A279183 Numbers k such that phi(6k) = phi(6k-2), where phi is Euler's totient function A000010.
%H A279183 Amiram Eldar, <a href="/A279183/b279183.txt">Table of n, a(n) for n = 1..761</a>
%H A279183 Dov Jarden, <a href="/A001602/a001602.pdf">Recurring Sequences</a>, Riveon Lematematika, Jerusalem, 1966. [Annotated scanned copy] See p. 67.
%t A279183 a = {}; Do[If[EulerPhi[6k] == EulerPhi[6 k - 2], AppendTo[a, k]], {k, 1000000}]; a (* _Vincenzo Librandi_, Dec 11 2016 *)
%o A279183 (Magma) [n: n in [1..2*10^6] | EulerPhi(6*n) eq EulerPhi(6*n-2)]; // _Vincenzo Librandi_, Dec 11 2016
%o A279183 (PARI) isok(k) = eulerphi(6*k) == eulerphi(6*k-2); \\ _Michel Marcus_, Dec 11 2016
%Y A279183 Cf. A000010.
%Y A279183 A279011 is the union of A279183 and A279184.
%K A279183 nonn
%O A279183 1,2
%A A279183 _N. J. A. Sloane_, Dec 10 2016
%E A279183 More terms from _Vincenzo Librandi_, Dec 11 2016