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%I #36 Sep 08 2022 08:45:47
%S 17,31,71,127,647,1151,2887,3527,7687,12799,19207,20807,23327,34847,
%T 39199,49927,53791,73727,79999,103967,117127,145799,172871,194687,
%U 220447,279751,294911,323207,336199,387199,394271,419527,438047,587527,649799,724807
%N Primes of the form 2*p^2 + 4*p + 1, where p is also prime.
%C A subsequence of the primes of the form 2k^2+4k+1 = 2*(k+1)^2-1, A066436. - _R. J. Mathar_, Aug 10 2009
%H Vincenzo Librandi, <a href="/A164041/b164041.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = 2*(A164042(n))^2 + 4*A164042(n) + 1.
%t lst={}; Do[p=Prime@n; a=2*p^2+4*p+1; If[PrimeQ@a,AppendTo[lst,a]],{n,7!}]; lst (* _Vladimir Joseph Stephan Orlovsky_, Aug 12 2009 *)
%t Select[Table[2p^2+4p+1,{p,Prime[Range[200]]}],PrimeQ] (* _Harvey P. Dale_, Aug 25 2019 *)
%o (Magma) [a: p in PrimesUpTo(700)|IsPrime(a) where a is 2*p^2+4*p+1 ] // _Vincenzo Librandi_, Sep 01 2012
%o (PARI) lista(nn) = {forprime(p=2, nn, if(isprime(q=2*p^2+4*p+1), print1(q, ", ")));} \\ _Altug Alkan_, Mar 29 2018
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Aug 08 2009
%E a(29) corrected by _R. J. Mathar_, Aug 11 2009
%E Edited by _N. J. A. Sloane_, Aug 11 2009