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 A141521 #6 Jul 08 2014 03:31:50
%S A141521 23,37,53,73,257,523
%N A141521 Primes with a prime number of digits, all of which are distinct primes.
%t A141521 Sort[Select[FromDigits/@Flatten[Permutations/@Subsets[{2,3,5,7},{2,3}],1],PrimeQ]] (* _Harvey P. Dale_, Jul 08 2014 *)
%Y A141521 Cf. A124888, A124674.
%K A141521 nonn,fini,full,base
%O A141521 1,1
%A A141521 _Lekraj Beedassy_, Aug 11 2008