A032508 Numbers k such that 263*2^k+1 is prime.

29, 85, 605, 1293, 1597, 27813, 89317, 249117

Offset

1,1

Links

Table of n, a(n) for n=1..8.

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[263*2^# + 1] & ] (* Robert Price, Dec 20 2018 *)

Prog

(PARI) is(n)=ispseudoprime(263*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A323218 A124784 A126383 * A042654 A042652 A042656

Adjacent sequences: A032505 A032506 A032507 * A032509 A032510 A032511

Keyword

hard,nonn,more

Author

N. J. A. Sloane.

Extensions

a(8) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 20 2018

Status

approved