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%I #14 Nov 12 2023 16:12:31
%S 29,31,37,109,271,757,59077,4782997,43046749,847288609471,
%T 717897987691852588770277,58149737003040059690390197,
%U 30903154382632612361920641803557,1824800363140073127359051977856583949
%N Primes of the form 3^k + 28.
%H Vincenzo Librandi, <a href="/A102906/b102906.txt">Table of n, a(n) for n = 1..23</a>
%F a(n) = 3^A219046(n) + 28. - _Elmo R. Oliveira_, Nov 12 2023
%t Select[Table[3^n+28,{n,0,1000}],PrimeQ] (* _Vincenzo Librandi_, Jul 19 2012 *)
%o (Magma) [ a: n in [0..100] | IsPrime(a) where a is 3^n+28 ]; // _Vincenzo Librandi_, Jul 19 2012
%Y Cf. A000040, A219046 (corresponding k's).
%K nonn
%O 1,1
%A _Roger L. Bagula_, Mar 01 2005
%E a(1) added by _Vincenzo Librandi_, Jul 19 2012