id:A067760 - OEIS Search Results

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a(n) = least positive k such that (2n+1)+2^k is prime.

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1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 3, 2, 1, 1, 4, 2, 1, 2, 1, 1, 2, 1, 5, 2, 1, 3, 2, 1, 1, 8, 2, 1, 2, 1, 1, 4, 2, 1, 2, 1, 7, 2, 1, 3, 4, 2, 1, 2, 1, 1, 2, 1, 1, 2, 1, 7, 4, 5, 3, 4, 2, 1, 2, 1, 3, 2, 1, 1, 10, 3, 3, 2, 1, 1, 4, 2, 1, 4, 2, 1, 2, 1, 5, 2, 1, 3, 2, 1, 1, 4, 3, 3, 2, 1, 1, 2, 1, 1, 6, 5, 3, 6 (list; graph; listen)

	OFFSET	`0,4`
	COMMENT	`Does a(1065) exist? (Is 2131+2^k composite for all positive k?)`
	LINKS	`T. D. Noe, Table of n, a(n) for n=0..1064` `C. Rivera, Prime Puzzles`
	EXAMPLE	`a(15)=4 because (2*15+1)+2^k is composite for k=1,2,3 and prime for k=4.`
	CROSSREFS	`Cf. A016014 A050412 A066081.` `Cf. A033919, A094076` `Sequence in context: A111178 A076845 A016014 this_sequence A078680 A050412 A025898` `Adjacent sequences: A067757 A067758 A067759 this_sequence A067761 A067762 A067763`
	KEYWORD	`nonn`
	AUTHOR	`Don Reble (djr(AT)nk.ca), Feb 05 2002`

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

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