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 A102903 #29 Nov 09 2023 11:03:09
%S A102903 5,7,13,31,733,19687,59053,31381059613,205891132094653,
%T A102903 109418989131512359213,1570042899082081611640534567,
%U A102903 323257909929174534292273980721360271853391
%N A102903 Primes of the form 3^k + 4.
%H A102903 Vincenzo Librandi, <a href="/A102903/b102903.txt">Table of n, a(n) for n = 1..17</a>
%F A102903 a(n) = 3^A058958(n) + 4. - _Elmo R. Oliveira_, Nov 09 2023
%t A102903 Select[Table[3^n+4,{n,0,200}],PrimeQ] (* _Vincenzo Librandi_, Jul 19 2012 *)
%o A102903 (Magma) [a: n in [0..100] | IsPrime(a) where a is 3^n+4]; // _Vincenzo Librandi_, Jul 19 2012
%Y A102903 Cf. A000040, A058958 (associated k).
%Y A102903 Cf. Primes of the form 3^k + d: A057735 (d=2), this sequence (d=4), A102870 (d=8), A102907 (d=10), A102874 (d=14), A243437 (d=16), A102904 (d=20), A243438 (d=22), A243439 (d=26), A102906 (d=28).
%K A102903 nonn
%O A102903 1,1
%A A102903 _Roger L. Bagula_, Mar 01 2005
%E A102903 Edited by _Zak Seidov_, Aug 29 2014