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 A101252 #11 Jan 24 2020 12:26:01
%S A101252 35729,35731,35747,35753,35759,35771,35797,357103,357107,357109,
%T A101252 357131,357139,357179,357197,357199,357211,357229,357239,357241,
%U A101252 357263,357271,357281,357283,357293,357347,357349,357353,357359,357389,357421,357431
%N A101252 Primes that are a concatenation of 3, 5, 7 and a prime.
%H A101252 Daniel Starodubtsev, <a href="/A101252/b101252.txt">Table of n, a(n) for n = 1..10000</a>
%H A101252 Peter Alfeld, <a href="http://www.math.utah.edu/~alfeld/math/p10000.html">The 10,000 smallest prime numbers</a>.
%e A101252 35729 is member as it is concatenated from the primes 3,5,7 and 29.
%t A101252 Select[ Table[ FromDigits[ Flatten[ IntegerDigits /@ {3, 5, 7, Prime[n]}]], {n, 95}], PrimeQ[ # ] &] (* _Robert G. Wilson v_, Dec 20 2004 *)
%Y A101252 Cf. A101218, A101219, A101249, A101250, A101251.
%K A101252 nonn,easy,base
%O A101252 1,1
%A A101252 _Parthasarathy Nambi_, Dec 16 2004
%E A101252 Extended by _Ray Chandler_ and _Robert G. Wilson v_, Dec 22 2004