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 A229814 #12 Oct 06 2013 09:27:20 %S A229814 23,1759,2383,41179,61283,71353,83431,127709,2271433,3372269,3532381, %T A229814 4993559,5033593,5714153,7275503,8876899,9117109,9377351,9717649, %U A229814 10618513,142711909,157913297,166314107,169314437,170914591,187116073,187716127,190716451,194916901 %N A229814 Primes which are a concatenation of prime(i) and prime(prime(i)) for some i. %H A229814 K. D. Bajpai, <a href="/A229814/b229814.txt">Table of n, a(n) for n = 1..10000</a> %e A229814 a(2)=1759: prime(7)= 17 and prime(17)= 59. Concatenating 17 and 59 gives 1759 which is prime. %e A229814 a(4)=41179: prime(13)= 41 and prime(41)= 179. Concatenating 41 and 179 gives 41179 which is prime. %p A229814 K := proc(n) local a,b,d; a :=ithprime(n); b:=ithprime(a); d:=parse(cat(a,b)); if isprime(d) then return (d) end if; end proc: %p A229814 seq(K(n), n=1..1000); %Y A229814 Cf. A030459, A045533. %K A229814 nonn,base,less %O A229814 1,1 %A A229814 _K. D. Bajpai_, Sep 30 2013