A160115 - OEIS

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A160115

Fluctuations of the number of cubefree integers not exceeding 2^n

0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 2, 2, 3, 0, -1, -1, 1, 2, 0, -1, 0, 2, 6, 1, 2, 7, 5, -1, -7, -4, 4, -7, -21, -7, -2, 30, 2, 14, -8, 7, -1, -7, -12, -1, 21, 28, 7, -29, -33, -76, -88, 15, 47, 58, -51, -112, 293, 122, 316, -96, -42, -259, 140, -111, 6, -790, -342, 146, 395, 1087 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,11`
	COMMENTS	`The asymptotic density of cubefree integers is the reciprocal of Apery's constant 1/zeta(3) = 0.83190737258... The number of cubefree integers not exceeding N is thus roughly N/zeta(3). When N is a power of 2, this sequence gives the difference between the actual number (A160113) and that linear estimate (rounded to the nearest integer).`
	LINKS	`G. P. Michon, Reciprocal of Apery's constant.` `G. P. Michon, On the number of cubefree integers not exceeding N.` `Eric Weisstein's World of Mathematics, Cubefree.`
	FORMULA	`a(n) = A160113(n)-round(2^n/zeta(3))`
	CROSSREFS	`A004709 (cube-free integers). A160112 & A160113 (counting cubefree integers).` `Sequence in context: A079243 A073438 A187096 * A139365 A071479 A182631` `Adjacent sequences: A160112 A160113 A160114 * A160116 A160117 A160118`
	KEYWORD	`easy,sign`
	AUTHOR	`Gerard P. Michon (g.michon(AT)att.net), May 06 2009`

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Last modified February 13 09:25 EST 2012. Contains 205451 sequences.