A032495 Numbers k such that 237*2^k+1 is prime.

4, 10, 52, 58, 59, 68, 82, 115, 247, 647, 2338, 2627, 4415, 8410, 17098, 38434, 42739, 59140, 100627, 104372, 127363, 137767, 173551, 234082, 243772, 585403, 1710490, 4153348, 5291999, 5315983

Offset

1,1

Links

Table of n, a(n) for n=1..30.

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[237*2^# + 1] & ] (* Robert Price, Dec 19 2018 *)

Prog

(PARI) is(n)=ispseudoprime(237*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A151611 A351046 A208236 * A109387 A362819 A018844

Adjacent sequences: A032492 A032493 A032494 * A032496 A032497 A032498

Keyword

nonn,hard,more,changed

Author

N. J. A. Sloane.

Extensions

a(19)-a(27) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 19 2018

a(28)-a(30) from Jeppe Stig Nielsen, Dec 21 2024

Status

approved