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 A107833 #2 Mar 30 2012 17:26:16 %S A107833 13,5,6,2,9,1,10,8,7,4,12,11,14,15,19,18,20,21,16,3,17,22,24,23,27,26, %T A107833 28,25,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49, %U A107833 50,51,52,53,54,55,56,57,58,59,60,61 %N A107833 Indices of primes occurring in A107813. %F A107833 A107833(n)=pi(A107813(n)) %Y A107833 Cf. A107801 - A107814, A107821, A107822, A107823, A107824, A107825, A107826, A107827, A107828, A107829, A107830, A107831, A107832, A107834. %K A107833 easy,nonn %O A107833 1,1 %A A107833 _Zak Seidov_, May 24 2005