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A032505
Numbers n such that 257*2^n+1 is prime.
1
279, 415, 711, 115807, 241071
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OFFSET
1,1
LINKS
Table of n, a(n) for n=1..5.
Ray Ballinger,
Proth Search Page
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
PROG
(PARI) is(n)=ispseudoprime(257*2^n+1) \\
Charles R Greathouse IV
, Jun 07 2017
CROSSREFS
Sequence in context:
A251624
A062384
A053345
*
A252855
A331265
A038656
Adjacent sequences:
A032502
A032503
A032504
*
A032506
A032507
A032508
KEYWORD
nonn
,
hard
AUTHOR
N. J. A. Sloane
.
EXTENSIONS
One more term (from the Ballinger-Keller web page) from
M. F. Hasler
, Apr 18 2007
STATUS
approved
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Last modified September 2 08:20 EDT 2024. Contains 375604 sequences. (Running on oeis4.)