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%I #39 Sep 08 2022 08:44:52
%S 1,3,5,9,11,13,19,21,23,25,31,33,35,41,45,49,51,53,59,63,65,69,73,75,
%T 79,89,91,93,101,103,109,111,115,121,123,125,131,135,139,143,145,151,
%U 153,161,165,173,179,181,189,191,199,201,203,205,209,213,219,223,229
%N Numbers k such that 3*k + 4 is prime.
%C Related to hyperperfect numbers of a certain form.
%H Daniel Starodubtsev, <a href="/A034936/b034936.txt">Table of n, a(n) for n = 1..10000</a>
%H J. S. McCranie, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL3/mccranie.html">A study of hyperperfect numbers</a>, J. Int. Seqs. Vol. 3 (2000) #P00.1.3.
%t lst={};Do[p=n+(n+1)+(n+3);If[PrimeQ[p],AppendTo[lst,n]],{n,5!}];lst (* _Vladimir Joseph Stephan Orlovsky_, May 22 2009 *)
%t Select[Range[300],PrimeQ[3#+4]&] (* _Harvey P. Dale_, Aug 25 2016 *)
%o (Magma) [n: n in [1..1000] |IsPrime(3*n+4)] // _Vincenzo Librandi_, Nov 17 2010
%o (PARI) is(n)=isprime(3*n+4) \\ _Charles R Greathouse IV_, Jul 02 2013
%Y Cf. A038536 and A002476.
%Y A002476 gives primes, A091178 gives prime index.
%Y a(n) = A024892(n) - 1 = 2*A024899(n) - 1.
%Y a(n) = A153183(n) - 2 = A107303(n) - 3.
%K nonn,easy
%O 1,2
%A _Jud McCranie_
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