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 A104070 #27 Jul 24 2025 03:25:48
%S A104070 11,13,17,41,73,137,521,1033,262153,8388617,1073741833,137438953481,
%T A104070 140737488355337,144115188075855881,73786976294838206473,
%U A104070 4835703278458516698824713,39614081257132168796771975177,664613997892457936451903530140172297
%N A104070 Primes of the form 2^k + 9.
%H A104070 Amiram Eldar, <a href="/A104070/b104070.txt">Table of n, a(n) for n = 1..34</a>
%F A104070 a(n) = 2^A057196(n) + 9. - _Elmo R. Oliveira_, Nov 08 2023
%t A104070 a = Delete[Union[Flatten[Table[If [PrimeQ[2^n + 9] == True, 2^ n + 9, 0], {n, 1, 400}]]], 1]
%t A104070 Select[2^Range[0,100]+9,PrimeQ] (* _Harvey P. Dale_, Mar 11 2023 *)
%o A104070 (Magma) [a: n in [0..250] | IsPrime(a) where a is 2^n+9]; // _Vincenzo Librandi_, Jan 26 2011
%Y A104070 Cf. A000040, A057196 (numbers k such that 2^k + 9 is prime). [From _Klaus Brockhaus_, Mar 14 2009]
%K A104070 nonn
%O A104070 1,1
%A A104070 _Roger L. Bagula_, Mar 02 2005