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 A257457 #5 Apr 29 2015 16:06:13 %S A257457 2,3,4,6,8,10,11,12,14,15,18,19,20,22,23,27,30,35,38,42,47,48,49,52, %T A257457 53,54,60,61,63,64,69,70,73,74,83,85,87,89,92,94,97,102,112,114,116, %U A257457 117,120,125,127,128,134,136,139,146,149,151,153,155,156,158,159 %N A257457 Indices of primes in A257339. %C A257457 A010051(a(n)) = 1. %H A257457 Reinhard Zumkeller, <a href="/A257457/b257457.txt">Table of n, a(n) for n = 1..10000</a> %o A257457 (Haskell) %o A257457 a257457 n = a257457_list !! (n-1) %o A257457 a257457_list = filter ((== 1) . a010051 . a257339) [1..] %Y A257457 Cf. A257339, A010051, A257458. %K A257457 nonn %O A257457 1,1 %A A257457 _Reinhard Zumkeller_, Apr 24 2015