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 A084667 #46 Sep 08 2022 08:45:11
%S A084667 23,47,613,1237,1759,1861,2383,27103,30113,35149,36151,41179,42181,
%T A084667 45197,46199,54251,56263,57269,58271,61283,71353,82421,83431,85439,
%U A084667 92479,93487,99523,115631,117643,119653,121661,123677,127709,136769,141811,145829,147853
%N A084667 Primes which are a concatenation of n and prime(n).
%C A084667 Is the sequence infinite? - _Zak Seidov_, Nov 19 2013
%H A084667 Zak Seidov, <a href="/A084667/b084667.txt">Table of n, a(n) for n = 1..20000</a>
%e A084667 a(3) = 613 because prime(6) = 13 and 613 is prime,
%e A084667 a(1000) = 761077477 because prime(7610) = 77477 and 761077477 is prime.
%e A084667 a(20000) = 2092142886529 because prime(209214) = 2886529 and 2092142886529 is prime.
%t A084667 Select[Table[FromDigits[Flatten[{IntegerDigits[n], IntegerDigits[Prime[n]]}]], {n, 1, 500}], PrimeQ] (* _Alonso del Arte_, Sep 22 2004 *)
%o A084667 (Magma) [p: n in [1..200] | IsPrime(p) where p is Seqint(Intseq(NthPrime(n)) cat Intseq(n))]; // _Bruno Berselli_, Sep 15 2015
%o A084667 (PARI) lista(NN) = for(k=1,NN,p=prime(k);if(isprime(j=k*10^#digits(p)+p),print1(j, ", "))) \\ _Jinyuan Wang_, Apr 05 2019
%Y A084667 Cf. A084669.
%K A084667 nonn,base
%O A084667 1,1
%A A084667 _Zak Seidov_, Jun 29 2003