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Search: id:A048744
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| A048744 |
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Numbers n such that 2^n - n is prime. |
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+0
8
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| 2, 3, 9, 13, 19, 21, 55, 261, 3415, 4185, 7353, 12213, 44169, 60975, 61011, 108049, 182451, 228271, 481801, 500899, 505431
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 261, p. 70, Ellipses, Paris 2008.
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LINKS
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Henri Lifchitz, Renaud Lifchitz, PRP Top Records. 2^n-n.
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EXAMPLE
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2^55 - 55 = 36028797018963913 is prime.
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MATHEMATICA
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Do[ If[ PrimeQ[ 2^n - n ], Print[ n ] ], {n, 0, 7353} ]
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CROSSREFS
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Cf. A000325, A081296, A052007.
Sequence in context: A155929 A032486 A123859 this_sequence A057293 A109662 A116222
Adjacent sequences: A048741 A048742 A048743 this_sequence A048745 A048746 A048747
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KEYWORD
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nonn,nice,hard
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AUTHOR
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G. L. Honaker, Jr. (honak3r(AT)gmail.com)
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EXTENSIONS
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261 and 3415 found by Warut Roonguthai (warut822(AT)yahoo.com)
4185 and 7353 are probable primes (the latter was found by Jud McCranie).
12213 found by Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 02 2001.
More terms from Henri Lifchitz contributed by Ray Chandler (rayjchandler(AT)sbcglobal.net), Mar 02 2007
Edited by T. D. Noe (noe(AT)sspectra.com), Oct 30 2008
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