id:A117206 - OEIS Search Results

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Squarefree positive integers n such that (2n-1) is also squarefree.

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	OFFSET	`1,2`
	COMMENT	`2*a(n) -1 = A117205(n)`
	EXAMPLE	`10 and 2*10 -1 = 19 are both squarefree, so 10 is in the sequence.`
	MAPLE	`with(numtheory): a:=proc(n) if abs(mobius(n))>0 and abs(mobius(2*n-1))>0 then n else fi end: seq(a(n), n=1..160); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 08 2006`
	CROSSREFS	`Cf. A005117, A117204, A117205.` `Sequence in context: A073170 A014689 A140869 this_sequence A026443 A032858 A030703` `Adjacent sequences: A117203 A117204 A117205 this_sequence A117207 A117208 A117209`
	KEYWORD	`nonn`
	AUTHOR	`Leroy Quet (qq-quet(AT)mindspring.com), Mar 02 2006`
	EXTENSIONS	`More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 08 2006`

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Last modified November 18 20:14 EST 2008. Contains 147244 sequences.

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