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A050883 Numbers n such that 249*2^n-1 is prime. 0
8, 9, 12, 41, 57, 156, 201, 249, 612, 956, 1617, 2064, 2091, 2547, 4512, 5696, 9608, 11444, 20556, 33896, 77079, 89004, 251036 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..23.

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(249*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Sequence in context: A063080 A167131 A109079 * A064164 A079525 A083131

Adjacent sequences:  A050880 A050881 A050882 * A050884 A050885 A050886

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

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Last modified May 8 18:28 EDT 2021. Contains 343666 sequences. (Running on oeis4.)