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 A257458 #4 Apr 29 2015 16:06:43 %S A257458 1,2,3,4,5,6,8,9,10,11,12,13,14,15,17,18,19,20,22,23,25,27,30,31,34, %T A257458 35,38,42,45,47,48,49,52,53,54,60,61,63,64,66,69,70,71,73,74,81,83,85, %U A257458 87,89,92,94,97,100,102,108,112,114,116,117,120,125,127,128 %N A257458 Indices of prime powers in A257339. %C A257458 A010055(a(n)) = 1. %H A257458 Reinhard Zumkeller, <a href="/A257458/b257458.txt">Table of n, a(n) for n = 1..10000</a> %o A257458 (Haskell) %o A257458 a257458 n = a257458_list !! (n-1) %o A257458 a257458_list = filter ((== 1) . a010055 . a257339) [1..] %Y A257458 Cf. A257339, A010055, A257457. %K A257458 nonn %O A257458 1,2 %A A257458 _Reinhard Zumkeller_, Apr 24 2015