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 A122548 #1 Sep 29 2006 03:00:00
%S A122548 3,57,111,3171,92329,313741,4347535,96167717,379838997,1011031071,
%T A122548 9113127131,137139149151,1571631671731,79181191193197,199211223227229,
%U A122548 2332392412512572,63269271277281283,293307311313317331
%N A122548 Let N = 35711171923293137..., the concatenation of the odd primes. a(n) is the n-digit number formed from the digits of N starting from the {n(n-1)/2 +1}th digit. Omit any leading zeros.
%H A122548 Paul Cooijmans, <a href="http://web.archive.org/web/20050302174449/http://members.chello.nl/p.cooijmans/gliaweb/tests/odds.html">Odds</a>.
%Y A122548 Cf. A066549.
%K A122548 base,nonn
%O A122548 1,1
%A A122548 Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 19 2006