A032473 Numbers k such that 193*2^k+1 is prime.

2, 4, 8, 12, 24, 28, 30, 70, 82, 100, 124, 134, 434, 478, 540, 708, 952, 1052, 1070, 1528, 1804, 2568, 2914, 3712, 16582, 17342, 23368, 23942, 35998, 72174, 142022, 160658, 177768, 215140, 238092, 313540, 461470, 484500, 868328, 880188, 1679938, 1728894

Offset

1,1

Links

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..48

Ray Ballinger, Proth Search Page

Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300

Wilfrid Keller, List of primes k.2^n - 1 for k < 300

Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

Maple

select(k->isprime(193*2^k+1), [$0..1000]); # Muniru A Asiru, Dec 18 2018

Mathematica

Select[Range[1000], PrimeQ[193*2^# + 1] & ] (* Robert Price, Dec 18 2018 *)

Prog

(PARI) is(n)=ispseudoprime(193*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A327480 A330022 A362261 * A084422 A175841 A293601

Adjacent sequences: A032470 A032471 A032472 * A032474 A032475 A032476

Keyword

nonn,hard,changed

Author

N. J. A. Sloane.

Extensions

a(31)-a(43) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 18 2018

Term moved from Data section to b-file, and more terms added to b-file, by Jeppe Stig Nielsen, Jan 19 2020

Status

approved