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 A138537 #12 Aug 12 2016 19:24:19 %S A138537 11,23,29,31,47,53,59,67,71,79,83,103,107,127,131,137,139,149,151,167, %T A138537 173,179,191,197,199,211,223,227,229,239,251,263,269,271,283,293,307, %U A138537 311,317,331,347,359,367,373,379,383,389,419,431,439,443,463,467,479 %N A138537 Primes p_n for which A140141(n) = 2p_n, where p_n = n-th prime (A000040). %C A138537 Perhaps the same as A058340, but need proof. - _Ray Chandler_, May 20 2008 %C A138537 The first member of this sequence not in A058340 is 295937. - _Robert Israel_, Aug 12 2016 %H A138537 Robert Israel, <a href="/A138537/b138537.txt">Table of n, a(n) for n = 1..20000</a> %p A138537 filter:= n -> isprime(n) and numtheory:-invphi(numtheory:-phi(n))[2] = 2*n: %p A138537 select(filter, [seq(i,i=2..1000)]); # _Robert Israel_, Aug 12 2016 %Y A138537 Cf. A000010, A000040, A039649, A058340, A140141. %K A138537 nonn %O A138537 1,1 %A A138537 _Vladimir Shevelev_, May 10 2008 %E A138537 Corrected and extended by _Ray Chandler_, May 20 2008