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 A075600 #5 Dec 05 2013 19:55:39 %S A075600 11,1117,211177,12111773,1121117731,1112111773139,811121117731399, %T A075600 18111211177313993,5181112111773139933,351811121117731399339, %U A075600 63518111211177313993399,11635181112111773139933991 %N A075600 a(1) = 11 and then the smallest prime that is obtained by placing digits on both sides of the previous term. Or smallest prime that encompasses a(n-1). %Y A075600 Cf. A075595, A075596, A075597, A075598, A075599, A075601, A075602. %K A075600 base,nonn %O A075600 1,1 %A A075600 _Amarnath Murthy_, Sep 28 2002 %E A075600 More terms from _Sascha Kurz_, Jan 20 2003