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 A030473 #17 Apr 14 2016 09:43:01 %S A030473 2357,67717379,838997101,139149151157,149151157163,383389397401, %T A030473 503509521523,557563569571,577587593599,587593599601,601607613617, %U A030473 613617619631,727733739743,937941947953,1181118711931201 %N A030473 Primes which are concatenations of 4 consecutive primes. %H A030473 Zak Seidov and Robert Israel, <a href="/A030473/b030473.txt">Table of n, a(n) for n = 1..10000</a> (n = 1..1205 from Zak Seidov) %p A030473 P:= select(isprime,[2,seq(p,p=3..10^4,2)]): %p A030473 select(isprime,[seq(P[i+3]+10^(1+ilog10(P[i+3]))*P[i+2] + 10^(2+ilog10(P[i+3])+ilog10(P[i+2]))*P[i+1] + 10^(3+ilog10(P[i+3])+ilog10(P[i+2])+ilog10(P[i+1]))*P[i], i=1..nops(P)-3)]); # _Robert Israel_, Apr 14 2016 %Y A030473 Cf. A030461, A030469, A086040, A086041. %K A030473 nonn,base %O A030473 1,1 %A A030473 _Patrick De Geest_ %E A030473 Edited by _Charles R Greathouse IV_, Apr 23 2010