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Primes of the form 3^k + 28.
2

%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