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A032380 Numbers k such that 61*2^k + 1 is prime. 0
4, 12, 48, 88, 168, 3328, 172428, 285652 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

Ray Ballinger, Proth Search Page

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

(MAGMA) [n: n in [1..3500] |IsPrime(61*2^n + 1)] // Vincenzo Librandi, Nov 20 2010

(PARI) is(n)=ispseudoprime(61*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A035310 A022016 A151441 * A057346 A255230 A253087

Adjacent sequences:  A032377 A032378 A032379 * A032381 A032382 A032383

KEYWORD

nonn,hard

AUTHOR

James R. Buddenhagen

EXTENSIONS

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

STATUS

approved

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Last modified November 18 07:22 EST 2019. Contains 329252 sequences. (Running on oeis4.)