id:A070548 - OEIS Search Results

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a(n)=Card(k 0<k<=n such that mu(k)=1).

+0
3

1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 5, 5, 5, 5, 5, 5, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 9, 10, 11, 11, 11, 12, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 17, 18, 18, 18, 18, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 21, 22, 22, 22, 23, 23, 23, 23 (list; graph; listen)

	OFFSET	`1,6`
	COMMENT	`mu(k)=1 if k is the product of an even number of distinct primes. See A057627 for moebius(k)=0.`
	PROGRAM	`(PARI) for(n=1, 150, print1(sum(i=1, n, if(moebius(i)-1, 0, 1)), ", "))`
	CROSSREFS	`Cf. A008683.` `Sequence in context: A097913 A029269 A088004 this_sequence A132011 A054893 A090617` `Adjacent sequences: A070545 A070546 A070547 this_sequence A070549 A070550 A070551`
	KEYWORD	`easy,nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), May 02 2002`

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

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