id:A064998 - OEIS Search Results

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a(n) = smallest prime p such that p*n! +/- 1 are twin primes.

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2, 2, 3, 2, 17, 7, 7, 3, 61, 29, 167, 401, 167, 19, 311, 461, 97, 919, 47, 71, 1483, 107, 13, 1571, 821, 1361, 769, 239, 163, 4229, 593, 373, 1571, 173, 6229, 3331, 1879, 2837, 2633, 12329, 2311, 269, 4159, 1217, 9719, 509, 3049, 8429, 307, 6121, 7919 (list; graph; listen)

	OFFSET	`2,1`
	EXAMPLE	`a(6) = 17 because (17*6! = 12240) 12240 + 1 and 12240 -1 are twin primes and there is no prime less than 17 for which this pairing will work.`
	MATHEMATICA	`Do[k = 1; While[ !PrimeQ[ Prime[k]n! - 1] \|\| !PrimeQ[ Prime[k]n! + 1], k++ ]; Print[ Prime[k]], {n, 2, 75} ]`
	CROSSREFS	`Cf. A051888, A064983.` `Sequence in context: A016008 A016009 A110088 this_sequence A127012 A125503 A127009` `Adjacent sequences: A064995 A064996 A064997 this_sequence A064999 A065000 A065001`
	KEYWORD	`nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 31 2001`

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.

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