A231982 - OEIS

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A231982

Decimal expansion of one deg^2 expressed in steradians (sr).

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

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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

Index entries for transcendental numbers

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