A053351 Numbers k such that 269*2^k + 1 is prime.

3, 5, 15, 27, 53, 137, 153, 155, 185, 239, 717, 735, 789, 1343, 3485, 5109, 6195, 14927, 110463, 132695, 143027, 183725, 216803, 317859, 469595, 1011107, 1317053, 1348497, 1618877, 1942389, 2189235, 2918105

Offset

1,1

Links

Table of n, a(n) for n=1..32.

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[5*10^3], PrimeQ[269*2^# + 1] &] (* G. C. Greubel, May 24 2018 *)

Prog

(PARI) is(n)=ispseudoprime(269*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
(Magma) [n: n in [1..300] | IsPrime(269*2^n+1)];  // G. C. Greubel, May 24 2018

Crossrefs

Sequence in context: A202212 A253790 A372430 * A289045 A289882 A288976

Adjacent sequences: A053348 A053349 A053350 * A053352 A053353 A053354

Keyword

hard,nonn,more

Author

N. J. A. Sloane, Dec 29 1999

Extensions

a(19)-a(30) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 20 2018

a(31)-a(32) from Jeppe Stig Nielsen, Jan 19 2020

Status

approved