A032471 Numbers k such that 189*2^k+1 is prime.

1, 2, 6, 9, 17, 39, 45, 95, 359, 526, 609, 783, 818, 917, 1445, 1590, 1606, 1861, 2037, 3538, 3730, 6186, 7482, 11801, 12162, 23838, 25785, 27565, 30666, 37033, 37518, 52082, 74127, 90061, 133599, 219966, 238202, 241297, 280502, 632049, 724746, 845142, 943329

Offset

1,2

Links

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..49

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(189*2^k+1), [$0..1000]); # Muniru A Asiru, Dec 18 2018

Mathematica

Select[Range[1000], PrimeQ[189*2^# + 1] & ] (* Robert Price, Dec 18 2018 *)

Prog

(PARI) is(n)=ispseudoprime(189*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A257083 A054974 A072481 * A358258 A156222 A002886

Adjacent sequences: A032468 A032469 A032470 * A032472 A032473 A032474

Keyword

nonn,hard

Author

N. J. A. Sloane

Extensions

a(35)-a(45) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 18 2018

Terms moved from Data section to b-file, and more terms added to b-file by Jeppe Stig Nielsen, Mar 12 2020

Status

approved