Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #29 Nov 09 2023 11:03:09
%S 5,7,13,31,733,19687,59053,31381059613,205891132094653,
%T 109418989131512359213,1570042899082081611640534567,
%U 323257909929174534292273980721360271853391
%N Primes of the form 3^k + 4.
%H Vincenzo Librandi, <a href="/A102903/b102903.txt">Table of n, a(n) for n = 1..17</a>
%F a(n) = 3^A058958(n) + 4. - _Elmo R. Oliveira_, Nov 09 2023
%t Select[Table[3^n+4,{n,0,200}],PrimeQ] (* _Vincenzo Librandi_, Jul 19 2012 *)
%o (Magma) [a: n in [0..100] | IsPrime(a) where a is 3^n+4]; // _Vincenzo Librandi_, Jul 19 2012
%Y Cf. A000040, A058958 (associated k).
%Y 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 nonn
%O 1,1
%A _Roger L. Bagula_, Mar 01 2005
%E Edited by _Zak Seidov_, Aug 29 2014