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 A090473 #5 Oct 01 2013 17:57:56 %S A090473 2,2,3,5,5,7,7,7,11,11,11,13,13,13,13,17,17,17,17,19,19,19,19,23,23, %T A090473 23,23,29,29,29,29,29,31,31,31,31,37,37,37,37,37,41,41,41,41,41,43,43, %U A090473 43,43,43,47,47,47,47,47,53,53,53,53,53,53,59,59,59,59,59,59,61,61,61,61 %N A090473 Primes in A047783. %C A090473 The logarithmic integral can be computed in PARI: Li(x) = -eint1(log(1/x)). %o A090473 (PARI) lip(n) = forstep(x=1,n,1,y=floor(-eint1(log(1/x)));if(isprime(y),print1(y","))) %Y A090473 Cf. A047783. %K A090473 easy,nonn %O A090473 1,1 %A A090473 _Cino Hilliard_, Feb 01 2004 %E A090473 Edited by _David Wasserman_, Nov 16 2005