A032483 Numbers k such that 213*2^k+1 is prime.

2, 6, 14, 17, 36, 62, 80, 84, 156, 726, 866, 2234, 4274, 5972, 17054, 17462, 21630, 145146, 217950, 391026, 546146, 573332, 906152, 978900, 1728569, 2226329

Offset

1,1

Links

Table of n, a(n) for n=1..26.

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

Mathematica

Select[Range[1000], PrimeQ[213*2^# + 1] & ] (* Robert Price, Dec 19 2018 *)

Prog

(PARI) is(n)=ispseudoprime(213*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A245289 A065196 A295326 * A057214 A196445 A280082

Adjacent sequences: A032480 A032481 A032482 * A032484 A032485 A032486

Keyword

nonn,hard,more

Author

N. J. A. Sloane.

Extensions

a(18)-a(25) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 19 2018

a(26) from Jeppe Stig Nielsen, Apr 19 2020

Status

approved