A032467 Numbers k such that 181*2^k+1 is prime.

4, 8, 32, 200, 272, 416, 484, 788, 3560, 6628, 44392, 64264, 75832, 80440, 94112, 315104, 359404, 428576, 608192, 1209572

Offset

1,1

Links

Table of n, a(n) for n=1..20.

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(181*2^k+1), [$0..1000]); # Muniru A Asiru, Dec 18 2018

Mathematica

Select[Range[1000], PrimeQ[181*2^# + 1] & ] (* Robert Price, Dec 18 2018 *)

Prog

(PARI) is(n)=ispseudoprime(181*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A261196 A222537 A208924 * A009265 A173326 A173652

Adjacent sequences: A032464 A032465 A032466 * A032468 A032469 A032470

Keyword

nonn,hard,more

Author

N. J. A. Sloane.

Extensions

a(16)-a(20) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 18 2018

Status

approved