A032488 Numbers k such that 223*2^k+1 is prime.

8, 10, 22, 44, 58, 62, 68, 82, 100, 104, 118, 230, 260, 440, 446, 512, 700, 892, 932, 1240, 1456, 2438, 4982, 5090, 6496, 14678, 17944, 23786, 27838, 39866, 46322, 52358, 61700, 68584, 78244, 180410, 397096, 404962, 693656, 803446, 871438, 1065400, 1356316

Offset

1,1

Links

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..48

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[223*2^# + 1] & ] (* Robert Price, Dec 19 2018 *)

Prog

(PARI) is(n)=ispseudoprime(223*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A292999 A374111 A216047 * A102844 A303199 A097543

Adjacent sequences: A032485 A032486 A032487 * A032489 A032490 A032491

Keyword

nonn,hard

Author

N. J. A. Sloane.

Extensions

a(36)-a(43) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 19 2018

Status

approved