login
A058592
Numbers k such that 7*2^k + 3 is prime.
1
1, 2, 3, 5, 13, 14, 21, 30, 50, 363, 391, 1418, 2541, 2803, 7334, 10229, 12078, 14034, 15949, 22878, 25554, 31554, 41739, 62931, 92443, 103863, 118843, 121669, 124839
OFFSET
1,2
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
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
a(25)-a(29) from Michael S. Branicky, Oct 23 2024
STATUS
approved