id:A126715 - OEIS Search Results

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a(n) = smallest odd prime p such that p*2^n - 1 is prime.

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3, 3, 3, 3, 3, 7, 3, 3, 5, 7, 5, 3, 5, 31, 5, 79, 17, 7, 3, 61, 17, 7, 83, 13, 83, 61, 11, 193, 83, 7, 521, 43, 5, 31, 3, 31, 17, 31, 3, 61, 107, 19, 53, 3, 557, 7, 23, 31, 5, 19, 11, 1033, 89, 307, 5, 3, 563, 79, 83, 733, 17, 79, 53, 61, 3, 67, 257, 43, 179, 139, 47, 73, 5, 421, 113 (list; graph; listen)

	OFFSET	`0,1`
	LINKS	`T. D. Noe, Table of n, a(n) for n=0..2500`
	MATHEMATICA	`f[n_] := Block[{k = 2}, While[ !PrimeQ[ Prime[k]2^n - 1], k++ ]; Prime@k]; Table[f@n, {n, 0, 74}] ( Robert G. Wilson v *)`
	CROSSREFS	`Sequence in context: A113215 A105591 A130497 this_sequence A158805 A163469 A105121` `Adjacent sequences: A126712 A126713 A126714 this_sequence A126716 A126717 A126718`
	KEYWORD	`nonn`
	AUTHOR	`Pierre CAMI (pierrecami(AT)tele2.fr), Feb 13 2007`
	EXTENSIONS	`More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 16 2007` `Entries checked by N. J. A. Sloane (njas(AT)research.att.com), Mar 02 2007 and some errors corrected.`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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