A111517 Numbers n such that (7*n + 1)/2 is prime.

3, 15, 19, 31, 39, 43, 51, 55, 75, 79, 99, 111, 123, 139, 159, 163, 171, 175, 183, 195, 211, 231, 235, 259, 279, 283, 291, 295, 303, 315, 319, 339, 343, 351, 379, 411, 415, 423, 435, 451, 459, 463, 475

Offset

1,1

Links

Table of n, a(n) for n=1..43.

Example

If n=279 then (7*n + 1)/2 = 977 (prime).

Mathematica

Select[Range[500], PrimeQ[(7#+1)/2]&] (* Harvey P. Dale, May 07 2011 *)

Prog

(PARI) is(n)=isprime((7*n+1)/2) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A039570 A032644 A124877 * A083545 A224872 A097571

Adjacent sequences: A111514 A111515 A111516 * A111518 A111519 A111520

Keyword

nonn,easy

Author

Parthasarathy Nambi, Nov 16 2005

Status

approved