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A060397 Smallest prime that divides k^2 + k + 2n + 1 for k = 0,1,2,.... 2
3, 3, 5, 3, 3, 11, 3, 3, 17, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 3, 41, 3, 3, 7, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 3, 7, 3, 3, 7, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 3, 11, 3, 3, 7, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 3, 7, 3, 3, 11, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 3, 7, 3, 3, 11, 3, 3, 5, 3, 3, 5, 3, 3, 5, 3, 3, 7, 3, 3, 7, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Bisection of A060395.

LINKS

T. D. Noe, Table of n, a(n) for n = 0..10000

C. Rivera, www.primepuzzles.net, Conjecture 17

FORMULA

a(n)=3 if n is equal to 0 or 1 mod 3.

EXAMPLE

To obtain a(3), 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.

CROSSREFS

Cf. A060380, A060392-A060398. A060398 gives values of k.

Sequence in context: A235649 A113965 A162277 * A014780 A216199 A073081

Adjacent sequences:  A060394 A060395 A060396 * A060398 A060399 A060400

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane, Apr 04 2001

EXTENSIONS

More terms from Matthew Conroy, Apr 18 2001

STATUS

approved

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Last modified September 26 16:43 EDT 2020. Contains 337374 sequences. (Running on oeis4.)