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 A105238 #6 Jul 18 2013 18:35:38
%S A105238 23252729,77798183,115117119121,197199201203,211213215217,
%T A105238 221223225227,227229231233,265267269271,281283285287,311313315317,
%U A105238 317319321323,343345347349,373375377379,397399401403,403405407409,433435437439
%N A105238 Primes concatenated from four consecutive odd numbers.
%H A105238 Harvey P. Dale, <a href="/A105238/b105238.txt">Table of n, a(n) for n = 1..1000</a>
%F A105238 For positive n: {Concatenate((2n+1), (2n+3), (2n+5), (2n+7))} Intersect {Primes A000040}.
%t A105238 Select[FromDigits/@(Flatten[IntegerDigits[#]]&/@Partition[Range[ 1,501,2],4,1]),PrimeQ] (* _Harvey P. Dale_, Jul 18 2013 *)
%Y A105238 Cf. A000040, A032625.
%K A105238 base,easy,nonn
%O A105238 1,1
%A A105238 _Jonathan Vos Post_, Apr 12 2005