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A064539
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Numbers n such that 2^n + n^2 is prime.
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3
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1, 3, 9, 15, 21, 33, 2007, 2127, 3759, 29355, 34653, 57285, 99069
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| 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
| 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
| Discussion group for the primality-testing program PrimeForm.
Henri Lifchitz, Renaud Lifchitz, PRP Top Records. 2^n+n^2.
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PROG
| (PARI) for(n=1, 5000, if(isprime(2^n+n^2), print(n)))
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CROSSREFS
| Cf. A001580, A061119, A072180.
Sequence in context: A114271 A137164 A108701 * A029482 A174786 A139419
Adjacent sequences: A064536 A064537 A064538 * A064540 A064541 A064542
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KEYWORD
| hard,nonn
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Oct 16 2001
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EXTENSIONS
| More terms from Hugo Pfoertner (hugo(AT)pfoertner.org), Jun 26 2004
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