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 A104065 #16 Jun 05 2025 00:42:45
%S A104065 5,11,53,347,16811,823547,40353611,678223072853,27368747340080916347
%N A104065 Primes of the form 7^k + 4.
%H A104065 Amiram Eldar, <a href="/A104065/b104065.txt">Table of n, a(n) for n = 1..16</a>
%F A104065 a(n) = 7^A096305(n) + 4. - _Amiram Eldar_, Jun 05 2025
%t A104065 a = Delete[Union[Flatten[Table[If [PrimeQ[7^n + 3 + 1] == True, 7^n + 3 + 1, 0], {n, 1, 400}]]], 1]
%t A104065 Select[7^Range[0,30]+4,PrimeQ] (* _Harvey P. Dale_, Jul 31 2021 *)
%Y A104065 Cf. A096305.
%K A104065 nonn
%O A104065 1,1
%A A104065 _Roger L. Bagula_, Mar 02 2005
%E A104065 Initial 5 from _Vincenzo Librandi_, Dec 10 2010