id:A101406 - OEIS Search Results

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a(n)= least k such that k^n*(k^n-1)-1 is prime.

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3, 2, 3, 2, 2, 3, 3, 19, 2, 2, 45, 7, 15, 7, 5, 5, 44, 2, 4, 3, 84, 62, 128, 5, 4, 90, 16, 37, 15, 11, 311, 15, 295, 72, 3, 3, 242, 2, 126, 64, 152, 11, 78, 26, 2, 13, 14, 26, 140, 2, 24, 16, 157, 4, 49, 13, 2, 123, 64, 16, 61, 206, 6, 76, 412, 31, 84, 23, 24, 9, 471, 26, 422, 227, 8 (list; graph; listen)

	OFFSET	`1,1`
	EXAMPLE	`2^5(2^5-1)-1=3231-1=991 prime so for n=5 a(5)=2.`
	MATHEMATICA	`a = {}; Do[ k = 1; While[c = k^n; t = c*(c - 1) - 1; ! PrimeQ[t], k++ ]; AppendTo[a, k]; , {n, 75}]; a (Ray Chandler, Jan 27 2005)`
	CROSSREFS	`Cf. A101446.` `Adjacent sequences: A101403 A101404 A101405 this_sequence A101407 A101408 A101409` `Sequence in context: A064654 A056564 A082844 this_sequence A097509 A095206 A049071`
	KEYWORD	`nonn`
	AUTHOR	`Pierre CAMI (pierrecami(AT)tele2.fr), Jan 24 2005`

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Last modified October 13 09:05 EDT 2008. Contains 145008 sequences.

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