A138067 - OEIS

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A138067

Least k > 1 such that (2n-1)^k + 2 is prime, or 0 if no such number exists.

2, 2, 3, 0, 2, 5, 0, 2, 105, 0, 2, 11, 0, 5, 3, 0, 2, 15, 0, 2, 9, 0, 2, 113, 0, 5, 7, 0, 2, 27, 0, 3, 3, 0, 3, 3, 0, 12, 61, 0, 2, 3, 0, 4, 255, 0, 8, 63, 0, 2, 9, 0, 2, 3473, 0, 2, 3, 0, 2, 15, 0, 2, 87, 0, 3, 23, 0, 36, 1861, 0, 4, 3, 0, 2, 5, 0, 3, 7, 0, 136, 425, 0, 11 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,1`
	COMMENTS	`a(3n+1) = 0 for n > 0.` `a(84) > 100000. - Ray Chandler, Aug 10 2011`
	LINKS	`Table of n, a(n) for n=1..83.`
	CROSSREFS	`Cf. A084713 (smallest prime of the form (2n-1)^k + 2, or 0 if no such number exists).` `Cf. A138066 (least k > 0 such that (2n-1)^k + 2 is prime, or 0 if no such number exists).` `Cf. A051783 (k such that 3^k + 2 is prime).` `Cf. A087885 (k such that 5^k + 2 is prime).` `Cf. A090649, A109076, A113480, A138048, A138049, A138050, A138051, A087886, A113481.` `Sequence in context: A307356 A091426 A053761 * A324348 A125093 A294898` `Adjacent sequences: A138064 A138065 A138066 * A138068 A138069 A138070`
	KEYWORD	`hard,nonn`
	AUTHOR	`Alexander Adamchuk, Mar 02 2008`
	EXTENSIONS	`a(54)-a(83) from Donovan Johnson, Oct 29 2008`
	STATUS	`approved`

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Last modified December 28 19:31 EST 2022. Contains 359109 sequences. (Running on oeis4.)