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 A034591 #19 Jul 30 2021 04:18:52
%S A034591 0,2,6,8,9,12,27,31,36,42,44,45,51,56,63,68,69,78,83,86,93,94,96,98,
%T A034591 102,104,105,108,115,117,118,123,126,132,138,150,151,154,156,157,160,
%U A034591 167,176,180,183,186,192,194,195,199,201,205,213,217,219,225,230,233
%N A034591 Numbers whose concatenation with the next prime yields a prime.
%e A034591 8 is a term because nextprime(8) = 11 and 811 is prime.
%t A034591 Select[Range[0,250],PrimeQ@FromDigits@Flatten[IntegerDigits/@{#,NextPrime@#}]&] (* _Giorgos Kalogeropoulos_, Jul 30 2021 *)
%o A034591 (PARI) isok(m) = isprime(eval(Str(m, nextprime(m+1)))); \\ _Michel Marcus_, Oct 03 2014 and Jul 30 2021
%Y A034591 See also A034592, A034593, A034594, A034596, A030459.
%K A034591 nonn,base
%O A034591 1,2
%A A034591 _Patrick De Geest_, Oct 15 1998