Svoboda | Graniru | BBC Russia | Golosameriki | Facebook
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A114348 The integer difference between (the n-dimensional unit sphere surface area minus the (n+1)-dimensional unit sphere volume) and the (n+2)-dimensional unit sphere volume. 1
-6, -3, 2, 9, 16, 22, 25, 26, 25, 22, 18, 14, 10, 7, 5, 3, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
a(n) = 0 for n >= 19. - G. C. Greubel, Feb 06 2021
REFERENCES
D. M. Y Sommerville, An Introduction to the Geometry of n dimensions, Dover Publications (1958), pages 136-137.
LINKS
Wikipedia, Hypersphere.
FORMULA
Let v(n) = pi^(n/2)/Gamma(n/2+1) be the volume of the n-dimensional unit sphere and s(n) = 2*Pi^(n/2)/Gamma(n/2) be its surface content. Then a(n) = floor(s(n)-v(n+1)-v(n+2)).
MATHEMATICA
Table[Floor[ (Pi^(n/2)/2)*( (n*(n+2)-2*Pi)/Gamma[n/2 +2] - 2*Sqrt[Pi]/Gamma[(n+3)/2])], {n, 50}] (* G. C. Greubel, Feb 06 2021 *)
CROSSREFS
Cf. A138219.
Sequence in context: A076214 A011488 A021162 * A280680 A272083 A357614
KEYWORD
sign,less
AUTHOR
Roger L. Bagula, Feb 08 2006; corrected Feb 08 2006
EXTENSIONS
Signs reintroduced by R. J. Mathar, Jul 23 2012
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 22 03:34 EDT 2024. Contains 375354 sequences. (Running on oeis4.)