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A050854
Numbers n such that 205*2^n-1 is prime.
0
1, 9, 39, 45, 49, 67, 75, 99, 129, 159, 177, 445, 721, 771, 829, 849, 865, 1971, 3045, 8397, 9019, 10749, 21037, 30529, 38349, 46257, 53577, 64695, 77451, 128019, 420297, 462261
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OFFSET
1,2
LINKS
Table of n, a(n) for n=1..32.
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(205*2^n-1) \\
Charles R Greathouse IV
, Jun 13 2017
CROSSREFS
Sequence in context:
A071238
A213583
A343521
*
A053181
A348545
A346950
Adjacent sequences:
A050851
A050852
A050853
*
A050855
A050856
A050857
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 September 14 11:47 EDT 2024. Contains 375921 sequences. (Running on oeis4.)