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 A104840 #10 Aug 25 2013 06:04:34
%S A104840 89793238462643383279,27950288419716939937,95028841971693993751,
%T A104840 86280348253421170679,42117067982148086513,10555964462294895493,
%U A104840 59334461284756482337,3486104543266482133,48610454326648213393
%N A104840 Primes from merging of 20 successive digits in decimal expansion of Pi.
%H A104840 Vincenzo Librandi, <a href="/A104840/b104840.txt">Table of n, a(n) for n = 1..1000</a>
%t A104840 With[{pi = FromDigits/@Partition[RealDigits[Pi, 10, 1000][[1]], 20, 1]}, Select[pi, PrimeQ]] (* _Vincenzo Librandi_, Apr 21 2013 *)
%Y A104840 Cf. A000796, A104819 - A104842.
%K A104840 nonn,base
%O A104840 1,1
%A A104840 _Zak Seidov_, Mar 27 2005