A032394 Numbers k such that 89*2^k+1 is prime.

1, 7, 9, 21, 37, 61, 589, 711, 1537, 1921, 3217, 4237, 26721, 31297, 58101, 155251, 225111, 398359, 472099, 503479, 543049, 1272457, 1338001, 1943337, 5519481

Offset

1,2

Links

Table of n, a(n) for n=1..25.

Ray Ballinger, Proth Search Page

Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300

Y. Gallot, Proth.exe: Windows Program for Finding Large Primes

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

Prog

(PARI) is(n)=ispseudoprime(89*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A125968 A147068 A147012 * A242988 A063486 A070423

Adjacent sequences: A032391 A032392 A032393 * A032395 A032396 A032397

Keyword

nonn,changed

Author

James R. Buddenhagen

Extensions

More terms from Hugo Pfoertner, Jun 20 2003

More terms (from http://web.archive.org/web/20161028080239/http://www.prothsearch.net/riesel.html), Joerg Arndt, Apr 07 2013

a(25) from Jeppe Stig Nielsen, Dec 23 2024

Status

approved