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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

Stanislav Sykora, Table of n, a(n) for n = 4..2000

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 A144189

Adjacent sequences:  A231978 A231979 A231980 * A231982 A231983 A231984

KEYWORD

nonn,cons,easy

AUTHOR

Stanislav Sykora, Nov 16 2013

STATUS

approved

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Last modified May 19 18:35 EDT 2022. Contains 353847 sequences. (Running on oeis4.)