A050861 - OEIS

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A050861

Numbers n such that 219*2^n-1 is prime.

0

7, 81, 381, 412, 657, 853, 1317, 3261, 3768, 6081, 14017, 19993, 25863, 31801, 40113, 48877, 558313

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..17.

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(219*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A058785 A373441 A171768 * A083226 A088735 A364322

Adjacent sequences: A050858 A050859 A050860 * A050862 A050863 A050864

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