A058592 Numbers k such that 7*2^k + 3 is prime.

1, 2, 3, 5, 13, 14, 21, 30, 50, 363, 391, 1418, 2541, 2803, 7334, 10229, 12078, 14034, 15949, 22878, 25554, 31554, 41739, 62931

Offset

1,2

Links

Table of n, a(n) for n=1..24.

Mathematica

Do[ If[ PrimeQ[ 7*2^n + 3 ], Print[ n ] ], {n, 5000} ]
Select[Range[10000], PrimeQ[7*2^# + 3] &] (* Vincenzo Librandi, Oct 03 2012 *)

Prog

(PARI) is(n)=ispseudoprime(7*2^n+3) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A058593 (7*2^k - 3 is prime).

Sequence in context: A264745 A251414 A145343 * A268509 A260594 A228940

Adjacent sequences: A058589 A058590 A058591 * A058593 A058594 A058595

Keyword

nonn,more

Author

Robert G. Wilson v, Dec 26 2000

Extensions

a(15) from Vincenzo Librandi, Oct 03 2012

a(16)-a(23) from Jinyuan Wang, Jan 20 2020

a(24) from Michael S. Branicky, Mar 18 2024

Status

approved