A050878 - OEIS

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A050878

Numbers n such that 239*2^n-1 is prime.

0

4, 92, 25780, 104956, 140116, 356300

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..6.

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

Kosmaj, Riesel list k<300.

PROG

(PARI) is(n)=ispseudoprime(239*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A221287 A177411 A219891 * A173362 A353089 A202899

Adjacent sequences: A050875 A050876 A050877 * A050879 A050880 A050881

KEYWORD

hard,nonn

AUTHOR

N. J. A. Sloane, Dec 29 1999

EXTENSIONS

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

STATUS

approved