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 A165555 #18 Sep 29 2024 11:57:28
%S A165555 53,523,541,547,571,5101,5107,5113,5167,5179,5197,5227,5233,5281,5347,
%T A165555 5419,5431,5443,5449,5479,5503,5521,5557,5563,5569,5641,5647,5653,
%U A165555 5659,5683,5701,5743,5821,5827,5839,5857,5881,5953,51031,51061,51109,51151,51193,51217
%N A165555 Primes obtained from other primes by prefixing a 5.
%C A165555 The primes are considered in increasing order. Primes with the same number of digits, the difference between adjacent terms seems to be a multiple of 3.
%H A165555 K. D. Bajpai, <a href="/A165555/b165555.txt">Table of n, a(n) for n = 1..10000</a>
%H A165555 Chris Caldwell, <a href="https://t5k.org/lists/small/10000.txt">The First 10,000 Primes</a>
%e A165555 5479 is a prime obtained by prefixing a 5 to the prime 479.
%p A165555 A165555:= n-> (parse(cat(5,ithprime(n)))): select(isprime, [seq((A165555(n), n=1..1000))]); # _K. D. Bajpai_, Jul 14 2017
%t A165555 Select[Table[FromDigits[Join[IntegerDigits[5], IntegerDigits[Prime[n]]]], {n, 500}], PrimeQ] (*_K. D. Bajpai_, Jul 14 2017 *)
%t A165555 Select[5*10^IntegerLength[#]+#&/@Prime[Range[200]],PrimeQ] (* _Harvey P. Dale_, Sep 29 2024 *)
%o A165555 (Magma)[k : p in PrimesUpTo (2000) | IsPrime (k) where k is Seqint (Intseq (p) cat Intseq (5))]; // _K. D. Bajpai_, Jul 14 2017
%o A165555 (PARI) lista(nn) = forprime(p=2, nn, if (isprime(q=eval(concat(5, Str(p)))), print1(q, ", "))); \\ _Michel Marcus_, Jul 29 2017
%Y A165555 Cf. A000040, A165243, A165292, A165444.
%K A165555 base,nonn
%O A165555 1,1
%A A165555 _Parthasarathy Nambi_, Sep 21 2009
%E A165555 More terms from _Vincenzo Librandi_, Dec 02 2010
%E A165555 Missing term 5449 inserted by _K. D. Bajpai_, Jul 14 2017