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 A237418 #12 Nov 29 2023 07:03:45
%S A237418 19,31,79,271,1039,4111,65551,4194319,67108879,1073741839,4294967311,
%T A237418 1099511627791,4398046511119,70368744177679,4722366482869645213711,
%U A237418 75557863725914323419151
%N A237418 Primes of the form 4^k + 15.
%C A237418 Subsequence of A144487.
%H A237418 Vincenzo Librandi, <a href="/A237418/b237418.txt">Table of n, a(n) for n = 1..26</a>
%F A237418 a(n) = 4^A253773(n) + 15. - _Elmo R. Oliveira_, Nov 28 2023
%e A237418 65551 is a term because 4^8 + 15 = 65551 is prime.
%t A237418 Select[Table[4^n + 15, {n, 1, 200}],PrimeQ]
%o A237418 (Magma) [a: n in [1..70] | IsPrime(a) where a is 4^n+15];
%Y A237418 Cf. A000040, A144487, A253773 (corresponding k's).
%K A237418 nonn,easy
%O A237418 1,1
%A A237418 _Vincenzo Librandi_, Feb 22 2014