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A050882
Numbers n such that 247*2^n-1 is prime.
0
133, 277, 805, 2341, 68845, 952069
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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(247*2^n-1) \\
Charles R Greathouse IV
, Jun 13 2017
CROSSREFS
Sequence in context:
A316630
A250766
A254692
*
A146233
A146181
A105984
Adjacent sequences:
A050879
A050880
A050881
*
A050883
A050884
A050885
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 April 25 06:42 EDT 2024. Contains 371964 sequences. (Running on oeis4.)