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A160114 Fluctuations of the number of cubefree integers not exceeding 10^n 1
0, 1, 2, 1, 0, -1, 3, 7, -10, -1, -7, -14, -59, 21, 34, -15, 103, -104, 302, -38, -514, -290, 1130, 504, 2466, 6813, -1854, 1590, -4879, 3963 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

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 10, this sequence gives the difference between the actual number (A160112) 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) = A160112(n)-round(10^n/zeta(3))

CROSSREFS

A004709 (cube-free integers). A160112 & A160113 (counting cubefree integers).

Sequence in context: A118345 A118350 A183135 * A109970 A116088 A136501

Adjacent sequences:  A160111 A160112 A160113 * A160115 A160116 A160117

KEYWORD

easy,sign

AUTHOR

Gerard P. Michon (g.michon(AT)att.net), May 06 2009

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Last modified February 13 08:12 EST 2012. Contains 205451 sequences.