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Search: id:A064539
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| A064539 |
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Numbers n such that 2^n + n^2 is prime. |
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+0
4
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| 1, 3, 9, 15, 21, 33, 2007, 2127, 3759, 29355, 34653, 57285, 99069
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Last three values 2^2007+2007^2, 2^2127+2127^2, 2^3759+3759^2 were proved prime with Primo.
n is always an odd multiple of 3 (except for the first term), i.e. a(n) is a subsequence of A016945. - Lekraj Beedassy (blekraj(AT)yahoo.com), Jan 01 2007
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REFERENCES
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J.-M. De Koninck & A. Mercier, 1001 Problemes en Theorie Classique Des Nombres, Problem 165 pp. 30, 160, Ellipses Paris 2004.
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LINKS
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Discussion group for the primality-testing program PrimeForm.
Henri Lifchitz, Renaud Lifchitz, PRP Top Records. 2^n+n^2.
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PROGRAM
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(PARI) for(n=1, 5000, if(isprime(2^n+n^2), print(n)))
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CROSSREFS
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Cf. A001580, A061119, A072180.
Sequence in context: A114271 A137164 A108701 this_sequence A029482 A139419 A058972
Adjacent sequences: A064536 A064537 A064538 this_sequence A064540 A064541 A064542
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KEYWORD
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hard,nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Oct 16 2001
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EXTENSIONS
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More terms from Hugo Pfoertner (hugo(AT)pfoertner.org), Jun 26 2004
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