A034936 Numbers k such that 3*k + 4 is prime.

1, 3, 5, 9, 11, 13, 19, 21, 23, 25, 31, 33, 35, 41, 45, 49, 51, 53, 59, 63, 65, 69, 73, 75, 79, 89, 91, 93, 101, 103, 109, 111, 115, 121, 123, 125, 131, 135, 139, 143, 145, 151, 153, 161, 165, 173, 179, 181, 189, 191, 199, 201, 203, 205, 209, 213, 219, 223, 229

Offset: 1

Author

Jud McCranie

Keywords

• nonn
• easy

Comments

Related to hyperperfect numbers of a certain form.

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..10000
• J. S. McCranie, A study of hyperperfect numbers, J. Int. Seqs. Vol. 3 (2000) #P00.1.3.

Crossrefs

Cf. A038536 and A002476.

A002476 gives primes, A091178 gives prime index.

a(n) = A024892(n) - 1 = 2*A024899(n) - 1.

a(n) = A153183(n) - 2 = A107303(n) - 3.

Programs

Magma

[n: n in [1..1000] |IsPrime(3*n+4)] // Vincenzo Librandi, Nov 17 2010

Mathematica

lst={};Do[p=n+(n+1)+(n+3);If[PrimeQ[p],AppendTo[lst,n]],{n,5!}];lst (* Vladimir Joseph Stephan Orlovsky, May 22 2009 *)
Select[Range[300],PrimeQ[3#+4]&] (* Harvey P. Dale, Aug 25 2016 *)

PARI

is(n)=isprime(3*n+4) \\ Charles R Greathouse IV, Jul 02 2013