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 A153503 #29 Oct 05 2024 09:39:54 %S A153503 2,3,5,7,13,17,19,29,31,229,2371,4003,33029,55457,58313,205963,1875553 %N A153503 Primes p such that 2^(p-1)+3 is prime. %C A153503 A prime p is in the sequence if and only if p-1 is in A057732. %e A153503 For p = 2, 2^(p-1)+3 = 5 is prime. %e A153503 For p = 17, 2^(p-1)+3 = 65539 is prime. %e A153503 For p = 31, 2^(p-1)+3 = 1073741827 is prime. %t A153503 Select[Prime[Range[3000]], PrimeQ[2^(# - 1) + 3] &] (* _Vincenzo Librandi_, Jun 09 2015 *) %o A153503 (Magma) [p: p in PrimesUpTo(2000) | IsPrime(2^(p-1) + 3)]; // _Vincenzo Librandi_, Jun 09 2015 %Y A153503 Cf. A057732 (numbers k such that 2^k + 3 is prime), A057736 (primes p such that 2^p + 3 is prime), A000043 (primes p such that 2^p - 1 is prime). %K A153503 nonn,more,hard %O A153503 1,1 %A A153503 _Vincenzo Librandi_, Dec 28 2008 %E A153503 Edited and a(13)-a(15) (based on A057732) added by _Klaus Brockhaus_, Jan 06 2009 %E A153503 a(16) from _Vincenzo Librandi_, Jun 09 2015 %E A153503 a(17) from _Amiram Eldar_, Aug 01 2024