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A231982 Decimal expansion of one deg^2 expressed in steradians (sr). 7
3, 0, 4, 6, 1, 7, 4, 1, 9, 7, 8, 6, 7, 0, 8, 5, 9, 9, 3, 4, 6, 7, 4, 3, 5, 4, 9, 3, 7, 8, 8, 9, 3, 5, 5, 3, 5, 5, 9, 0, 6, 4, 7, 9, 6, 5, 1, 9, 7, 7, 7, 4, 8, 8, 4, 6, 9, 5, 4, 7, 8, 2, 0, 2, 5, 3, 7, 0, 5, 0, 8, 7, 1, 1, 1, 7, 0, 3, 8, 6, 5, 5, 2, 4, 7, 4, 6, 0, 9, 2, 7, 0, 7, 3, 6, 2, 7, 2, 3, 2, 0, 4, 4, 4, 5 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

-3,1

COMMENTS

This is the conversion ratio between two solid-angle measures: degree-square's and steradians, applicable to integration infinitesimals. A deg^2 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).

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 = -3..1998

Wikipedia, Steradian

Wikipedia, Square degree

FORMULA

(Pi/180)^2.

EXAMPLE

0.00030461741978670859934674354937889355355906479651977748846954782...

MATHEMATICA

RealDigits[(Pi/180)^2, 10, 120][[1]] (* Harvey P. Dale, Feb 20 2015 *)

CROSSREFS

Cf. A000796 (Pi), A072097 (rad/deg), A019685 (deg/rad), A231981 (inverse, sr/deg^2), A231983 (square with 1 deg side, in sr), A231984 (square with 1 deg side, in deg^2), A231985, A231986 (square with 1 rad side, in sr), A231987.

Sequence in context: A192878 A126826 A231983 * A198575 A112256 A188720

Adjacent sequences:  A231979 A231980 A231981 * A231983 A231984 A231985

KEYWORD

nonn,cons,easy

AUTHOR

Stanislav Sykora, Nov 16 2013

STATUS

approved

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Last modified May 22 16:19 EDT 2017. Contains 286882 sequences.