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 A217198 #20 Oct 16 2017 02:42:41 %S A217198 3,7,31,37,97,139,157,199,211,229,271,307,331,337,367,379,439,499,547, %T A217198 577,601,607,619,691,727,811 %N A217198 A sequence of odd primes p such that 2p-1 is prime and no p is equal to any 2q-1 with q in the sequence. %C A217198 Sequence used in conjunction with A001259 in the referenced articles. %C A217198 It is not clear that this sequence is correct -- it certainly does not match the title. See A217199 for the correct version. - _T. D. Noe_, Sep 28 2012 %H A217198 A. Schinzel and Andrzej Wakulicz, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa4/aa431.pdf">Sur l'équation phi(x+k)=phi(x), I.</a>, Acta Arith. 4 (1958), 181-184. %H A217198 A. Schinzel and Andrzej Wakulicz, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa5/aa546.pdf">Sur l'équation phi(x+k)=phi(x). II</a>. Acta Arith. 5 1959 425-426. %Y A217198 Cf. A001259, A110581, A217199. %K A217198 nonn %O A217198 1,1 %A A217198 _Michel Marcus_, Sep 27 2012