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A005849
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Prime Cullen numbers: numbers n such that n*2^n + 1 is prime.
(Formerly M5401)
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11
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1, 141, 4713, 5795, 6611, 18496, 32292, 32469, 59656, 90825, 262419, 361275, 481899, 1354828, 6328548
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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REFERENCES
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J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 141, p. 48, Ellipses, Paris 2008.
H. Dubner, Generalized Cullen numbers, J. Rec. Math., 21 (No. 3, 1989), 190-191.
P. Ribenboim, The Book of Prime Number Records. Springer-Verlag, NY, 2nd ed., 1989, p. 283.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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Table of n, a(n) for n=1..15.
Ray Ballinger, Cullen Primes: Definition and Status
C. K. Caldwell, Cullen Primes
R. Ondrejka, The Top Ten: a Catalogue of Primal Configurations
Primegrid, Home Page
Eric Weisstein's World of Mathematics, Cullen Number
Eric Weisstein's World of Mathematics, Integer Sequence Primes
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MATHEMATICA
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lst={}; Do[If[PrimeQ[n*2^n+1], Print[n]; AppendTo[lst, n]], {n, 10^9}]; lst [From Vladimir Joseph Stephan Orlovsky, Aug 21 2008]
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CROSSREFS
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Cf. A002064, A050920, A002234.
Sequence in context: A204469 A201553 A186955 * A172633 A221104 A202045
Adjacent sequences: A005846 A005847 A005848 * A005850 A005851 A005852
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KEYWORD
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hard,nonn,nice,more
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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a(14)=1354828 from http://www.prothsearch.net/cullen.html - Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Apr 20 2006
The term 1467763 was added in error and has now been deleted. Jens Kruse Andersen, Nov 28 2007, remarks that 1467763*2^1467763-1 is a Woodall prime, but 3 divides the Cullen number 1467763*2^1467763+1.
6328548 from John Blazek, May 14 2009. He later reports that the search of the range from 6300000 to 6328548 was completed on May 28 2009.
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STATUS
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approved
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