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 A049493 #20 Dec 29 2024 19:29:25
%S A049493 3,7,37,43,67,163,757,823,967,1087,1213,1303,1423,2293,2377,3187,3343,
%T A049493 3847,5653,5923,8677,8803,9157,9277,9787,11257,11617,11923,12097,
%U A049493 13693,14653,14767,14827,15667,15733,16417,18127,18397,20113,20743,26293
%N A049493 Numbers n such that n and n+4^k are all primes for k=1,2,3.
%H A049493 Harvey P. Dale, <a href="/A049493/b049493.txt">Table of n, a(n) for n = 1..1000</a>
%F A049493 A049492 INTERSECT A049490. - _R. J. Mathar_, Mar 26 2024
%e A049493 3, 3+4=7, 3+16=19, 3+64=67 are all primes.
%t A049493 Select[Prime[Range[3000]],And@@PrimeQ[#+4^{1,2,3}]&] (* _Harvey P. Dale_, Dec 26 2013 *)
%t A049493 Select[Prime[Range[3000]],AllTrue[#+{4,16,64},PrimeQ]&] (* _Harvey P. Dale_, Dec 29 2024 *)
%o A049493 (PARI) isok(n) = isprime(n) && isprime(n+4) && isprime(n+16) && isprime(n+64); \\ _Michel Marcus_, Dec 22 2013
%Y A049493 Subsequence of A049492.
%K A049493 nonn
%O A049493 1,1
%A A049493 _Labos Elemer_