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A060395
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Smallest prime that divides k^2 + k + n for k = 0, 1, 2, ....
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2
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2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 11, 2, 3, 2, 3, 2, 17, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 41, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 11
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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LINKS
| Matthew M. Conroy, Home page (listed instead of email address)
C. Rivera, www.primepuzzles.net, Conjecture 17
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FORMULA
| a(n)=2 if n is equal to 0, 2 or 4 modulo 6; a(n)=3 if n is equal to 1 or 3 modulo 6.
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EXAMPLE
| To obtain a(7), note that x^2+x+7 takes the values 7,9,13,19,... for k=0,1,2,... and the smallest prime dividing these numbers is 3.
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CROSSREFS
| Cf. A060380, A060392-A060398. A060396 gives values of k.
Sequence in context: A053669 A112047 A112048 * A016026 A086757 A166985
Adjacent sequences: A060392 A060393 A060394 * A060396 A060397 A060398
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KEYWORD
| nonn,easy,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Apr 04 2001
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EXTENSIONS
| More terms from Matthew M. Conroy, Apr 18 2001
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