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 A069690 #12 Nov 07 2022 13:18:37
%S A069690 2,19,23,31,41,43,47,53,61,67,71,73,83,101,107,109,113,149,163,193,
%T A069690 211,239,241,263,269,277,313,317,331,347,373,397,409,421,439,443,499,
%U A069690 521,523,541,547,607,617,619,641,647,673,677,757,787,829,863,877,907,911
%N A069690 Primes that yield another prime on placing a 9 on both sides (as leading and trailing digits).
%H A069690 Robert Israel, <a href="/A069690/b069690.txt">Table of n, a(n) for n = 1..10000</a>
%e A069690 241 belongs to this sequence as 92419 is also a prime.
%p A069690 filter:= proc(n) isprime(9+10*n+9*10^(2+ilog10(n))) end proc:
%p A069690 select(filter, [seq(ithprime(i),i=1..1000)]); # _Robert Israel_, Feb 02 2021
%t A069690 Select[ Range[2000], PrimeQ[ # ] && PrimeQ[ FromDigits[ Insert[ IntegerDigits[ # ], 9, {{1}, {-1}}]]] &]
%t A069690 Select[Prime[Range[200]],PrimeQ[FromDigits[Join[{9},IntegerDigits[#],{9}]]]&] (* _Harvey P. Dale_, Nov 07 2022 *)
%o A069690 (Python)
%o A069690 from sympy import isprime, primerange
%o A069690 def ok(p): return isprime(int('9'+str(p)+'9'))
%o A069690 def aupto(lim): return [p for p in primerange(2, lim+1) if ok(p)]
%o A069690 print(aupto(911)) # _Michael S. Branicky_, Feb 19 2021
%Y A069690 Cf. A069687, A069688, A069689.
%K A069690 nonn,base
%O A069690 1,1
%A A069690 _Amarnath Murthy_, Apr 06 2002
%E A069690 Edited and extended by _Robert G. Wilson v_, May 03 2002