A107304 Numbers k such that 5k - 7 is prime.

2, 4, 6, 10, 12, 16, 18, 22, 24, 34, 36, 40, 46, 48, 54, 58, 60, 64, 72, 76, 78, 88, 90, 94, 102, 106, 114, 120, 124, 130, 132, 136, 138, 148, 150, 156, 166, 172, 174, 178, 192, 198, 204, 208, 214, 220, 222, 226, 232, 234, 240, 244, 246, 258, 262, 276, 286, 288

Offset

1,1

Comments

5 and 7 are twin primes.

Links

Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Example

If k=2, then 5*k - 7 = 3 (prime).
If k=34, then 5*k - 7 = 163 (prime).

Mathematica

Select[Range[2, 300], PrimeQ[5#-7]&] (* Harvey P. Dale, May 22 2013 *)

Prog

(Magma) [n: n in [2..300]| IsPrime(5*n-7)]; // Vincenzo Librandi, Nov 13 2010
(PARI) is(n)=isprime(5*n-7) \\ Charles R Greathouse IV, Dec 27 2013
(PARI) [n\5+2 | n<-primes(10^3), n%5==3] \\ Charles R Greathouse IV, Dec 27 2013

Crossrefs

Cf. A030431.

Sequence in context: A105965 A229489 A355643 * A082417 A161842 A249434

Adjacent sequences: A107301 A107302 A107303 * A107305 A107306 A107307

Keyword

nonn

Author

Parthasarathy Nambi, May 20 2005

Extensions

More terms from Kyle D. Balliet, Feb 28 2009

Status

approved