A032482 Numbers k such that 211*2^k+1 is prime.

20, 28, 32, 192, 380, 1408, 1672, 2736, 6276, 8140, 31156, 40036, 166252, 287388, 449788, 456840

Offset

1,1

Links

Table of n, a(n) for n=1..16.

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[211*2^# + 1] & ] (* Robert Price, Dec 19 2018 *)

Prog

(PARI) is(n)=ispseudoprime(211*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A194674 A059617 A122146 * A024411 A269986 A139805

Adjacent sequences: A032479 A032480 A032481 * A032483 A032484 A032485

Keyword

nonn,hard,more

Author

N. J. A. Sloane.

Extensions

a(13)-a(16) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 19 2018

Status

approved