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 A057733 #37 Jul 25 2025 16:04:07
%S A057733 5,7,11,19,67,131,4099,32771,65539,262147,268435459,1073741827,
%T A057733 36028797018963971,147573952589676412931,19342813113834066795298819,
%U A057733 431359146674410236714672241392314090778194310760649159697657763987459
%N A057733 Primes of the form 2^k + 3.
%H A057733 Robert Israel, <a href="/A057733/b057733.txt">Table of n, a(n) for n = 1..25</a>
%H A057733 Christian Kassel and Christophe Reutenauer, <a href="https://arxiv.org/abs/2507.15780">Pairs of intertwined integer sequences</a>, arXiv:2507.15780 [math.NT], 2025. See p. 12.
%F A057733 a(n) = 2^A057732(n) + 3. - _Elmo R. Oliveira_, Nov 08 2023
%p A057733 for n from 1 to 2000 do `if`(isprime(2^n + 3), 2^n + 3, NULL) od;
%p A057733 # alternative:
%p A057733 select(isprime, [seq(2^n+3,n=1..2000)]); # _Robert Israel_, Dec 28 2015
%t A057733 Select[Table[2^n + 3, {n, 230}], PrimeQ] (* _Jayanta Basu_, May 23 2013 *)
%o A057733 (Magma) [ a: n in [0..250] | IsPrime(a) where a is 2^n+3 ] // _Vincenzo Librandi_, Aug 07 2010
%o A057733 (PARI) for(n=1,99,if(ispseudoprime(t=2^n+3),print1(t", "))) \\ _Charles R Greathouse IV_, Jul 02 2013
%Y A057733 Cf. A000040, A057732.
%K A057733 nonn
%O A057733 1,1
%A A057733 _G. L. Honaker, Jr._, Oct 29 2000
%E A057733 More terms from Francois Jooste (pin(AT)myway.com), Mar 17 2003