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A128001 Numbers n such that (n-1)*2^n+1 is prime. 2
2, 3, 7, 27, 51, 55, 81, 1471, 1483, 8668, 10885, 20803, 32605, 36391, 57004, 61627, 88651, 89731 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
MATHEMATICA
Select[Range[200], PrimeQ[(# - 1)*2^# + 1] &] (* G. C. Greubel, May 08 2018 *)
PROG
(PARI) is(n)=ispseudoprime((n-1)<<n+1) \\ Charles R Greathouse IV, Jun 06 2017
CROSSREFS
Sequence in context: A089708 A107881 A371161 * A264829 A156142 A052877
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Jan 25 2008
EXTENSIONS
a(8)-a(14) from Jason Earls, Jan 29 2008
a(15)-a(18) from Charles R Greathouse IV, Oct 09 2011
STATUS
approved

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Last modified April 14 16:12 EDT 2024. Contains 371665 sequences. (Running on oeis4.)