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 A237438 #15 Feb 08 2014 15:06:45 %S A237438 2,3,5,7,11,43,47,53,59,61,89,97,101,139,151,167,199,241,251,257,269, %T A237438 281,337,373,443,557,599,607,647,653,829,971,1051,1093,1163,1223,1279, %U A237438 1327,1433,1459,1499,1549,1583,1597,1607 %N A237438 Double Hex-primes: let f(n) = A102489(n); then sequence lists primes p such that f(p) and f(f(p)) are also primes. %C A237438 This sequence is a subset of A103144. %H A237438 Andreas Boe, <a href="/A237438/b237438.txt">Table of n, a(n) for n = 1..6084</a> %e A237438 Dec61=prime -> Hex61=Dec97=prime -> Hex97=Dec151=prime. %Y A237438 Cf. A102489. %Y A237438 Cf. A103144 (Hex-primes), A237439 (Triple Hex-primes), A237440 (Quadruple Hex-primes), A237441 (Quintuple Hex-primes). %K A237438 nonn,base %O A237438 1,1 %A A237438 _Andreas Boe_, Feb 07 2014