A155722 Numbers k such that 2*k + 9 is prime.

1, 2, 4, 5, 7, 10, 11, 14, 16, 17, 19, 22, 25, 26, 29, 31, 32, 35, 37, 40, 44, 46, 47, 49, 50, 52, 59, 61, 64, 65, 70, 71, 74, 77, 79, 82, 85, 86, 91, 92, 94, 95, 101, 107, 109, 110, 112, 115, 116, 121, 124, 127, 130, 131, 134, 136, 137, 142, 149, 151, 152, 154, 161, 164

Offset

1,2

Comments

Subsequence of A001651; A011655(a(n)) = 1. - Reinhard Zumkeller, Jul 09 2010

One less than the associated entry in A105760, two less than in A089038, three less than in A067076. - R. J. Mathar, Jan 05 2011

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

(Prime[Range[5, 100]] - 9)/2 (* Vladimir Joseph Stephan Orlovsky, Feb 08 2010 *)
Select[Range[0, 200], PrimeQ[2 # + 9]&] (* Vincenzo Librandi, Sep 24 2012 *)

Prog

(Magma) [n: n in [0..200] | IsPrime(2*n+9)]; // Vincenzo Librandi, Sep 24 2012
(PARI) is(n)=isprime(2*n+9) \\ Charles R Greathouse IV, Jul 12 2016
(Sage) [n for n in (0..200) if is_prime(2*n+9) ] # G. C. Greubel, May 21 2019
(GAP) Filtered([0..200], k-> IsPrime(2*k+9) ) # G. C. Greubel, May 21 2019

Crossrefs

Cf. A155723, A155724.

Numbers h such that 2*h + k is prime: A005097 (k=1), A067076 (k=3), A089038 (k=5), A105760 (k=7), this seq (k=9), A101448 (k=11), A153081 (k=13), A089559 (k=15), A173059 (k=17), A153143 (k=19).

Sequence in context: A039672 A014370 A095278 * A049045 A153766 A319301

Adjacent sequences: A155719 A155720 A155721 * A155723 A155724 A155725

Keyword

nonn,easy

Author

Vincenzo Librandi, Jan 25 2009

Extensions

Edited by N. J. A. Sloane, Jun 23 2010

Definition clarified by Zak Seidov, Jul 11 2014

Status

approved