login
This site is supported by donations to The OEIS Foundation.

 

Logo

The OEIS is looking to hire part-time people to help edit core sequences, upload scanned documents, process citations, fix broken links, etc. - Neil Sloane, njasloane@gmail.com

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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; text; 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

Table of n, a(n) for n=0..29.

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 (cubefree integers). A160112 & A160113 (counting cubefree integers).

Sequence in context: A287316 A210472 A246106 * A213028 A109970 A116088

Adjacent sequences:  A160111 A160112 A160113 * A160115 A160116 A160117

KEYWORD

easy,sign

AUTHOR

Gerard P. Michon, May 06 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified May 27 22:57 EDT 2017. Contains 287210 sequences.