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!)
A231981 Decimal expansion of one steradian (sr) expressed in square degrees. 7
3, 2, 8, 2, 8, 0, 6, 3, 5, 0, 0, 1, 1, 7, 4, 3, 7, 9, 4, 7, 8, 1, 6, 9, 4, 6, 0, 7, 9, 9, 5, 1, 7, 5, 5, 0, 0, 5, 0, 1, 2, 2, 4, 2, 9, 9, 3, 8, 0, 7, 8, 8, 1, 8, 2, 5, 9, 7, 7, 3, 2, 6, 3, 3, 3, 7, 1, 2, 0, 9, 1, 1, 9, 1, 7, 6, 4, 2, 8, 2, 9, 4, 5, 9, 5, 1, 8, 0, 4, 7, 5, 1, 9, 0, 1, 4, 7, 5, 3, 8, 6, 8, 1, 3, 6 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
4,1
COMMENTS
This is the conversion ratio between two solid-angle measures: steradians and square degrees, applicable to integration infinitesimals. The square degree must not be confused with a finite spherical square having one degree side (see A231983, A231984, A231985), just as one steradian must not be confused with the solid angle covered by a spherical square with a side arc-length of one radian (see A231986, A231987).
Equals also full solid angle expressed in degrees, divided by 4*Pi (i.e., A125560/(4*Pi)).
REFERENCES
G. V. Brummelen, Heavenly Mathematics: The Forgotten Art of Spherical Trigonometry, Princeton University Press, 2012, ISBN 978-0691148922.
LINKS
Wikipedia, Steradian
Wikipedia, Square degree
FORMULA
(180/Pi)^2.
EXAMPLE
3282.80635001174379478169460799517550050122429938078818259773...
MATHEMATICA
RealDigits[(180/Pi)^2, 10, 120][[1]] (* Harvey P. Dale, Nov 23 2019 *)
CROSSREFS
Cf. A000796 (Pi), A125560 (full solid angle), A072097 (rad/deg), A019685 (deg/rad), A231982 (inverse, deg^2/sr), A231983 (square with 1 deg side, in sr), A231984 (square with 1 deg side, in square degrees), A231985, A231986 (square with 1 rad side, in sr), A231987.
Sequence in context: A113794 A086774 A153461 * A344577 A019666 A110938
KEYWORD
nonn,cons,easy
AUTHOR
Stanislav Sykora, Nov 16 2013
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 March 28 16:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)