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 A089703 #4 Dec 05 2013 19:56:36 %S A089703 2,23,233,2333,23333,2333323,233332343,23333234359,2333323435967, %T A089703 233332343596783,233332343596783199,233332343596783199239, %U A089703 233332343596783199239421,233332343596783199239421569 %N A089703 Primes arising in A089702. %Y A089703 Cf. A089702. %K A089703 base,nonn %O A089703 1,1 %A A089703 _Amarnath Murthy_, Nov 10 2003 %E A089703 More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 25 2004