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A217572 Decimal expansion of the conversion factor from radians to arcseconds. 10
2, 0, 6, 2, 6, 4, 8, 0, 6, 2, 4, 7, 0, 9, 6, 3, 5, 5, 1, 5, 6, 4, 7, 3, 3, 5, 7, 3, 3, 0, 7, 7, 8, 6, 1, 3, 1, 9, 6, 6, 5, 9, 7, 0, 0, 8, 7, 9, 6, 3, 1, 5, 5, 7, 5, 7, 6, 9, 7, 6, 8, 7, 7, 9, 0, 0, 3, 3, 0, 2, 4, 9, 7, 3, 3 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
6,1
COMMENTS
From Peter Munn, Aug 21 2020 and Nov 11 2020: (Start)
Corresponds to a significant mark labeled with a (typographic) double prime symbol on slide rule calculating devices in the 20th century. The Pickworth reference explains its use for sines and tangents of small angles.
As tangents of small angles can be approximated by the angle itself, this value approximates the cotangent of an arcsecond, and so, to within 1 part in 10^11, the number of astronomical units in a parsec, prior to its redefinition in August 2015. (End)
Equals the number of astronomical units in a parsec, as defined in 2015. - Donghwi Park, Aug 08 2021
REFERENCES
C. N. Pickworth, The Slide Rule, 24th Ed., Pitman, London, 1945, pp. 76-78, Trigonometrical Applications.
LINKS
Wikipedia, Parsec.
FORMULA
Equals 3600 * A072097.
Equals 1/A155970.
EXAMPLE
206264.806247096355156473...
MAPLE
evalf(180/Pi*3600) ;
MATHEMATICA
RealDigits[(180/Pi) 3600, 10, 75][[1]] (* Bruno Berselli, Oct 10 2012 *)
PROG
(Maxima) fpprec:77; ev(bfloat((180/%pi)*3600)); \\ Bruno Berselli, Oct 10 2012
CROSSREFS
Related conversion factors: A155970 (arcseconds to radians), A072097 (radians to degrees), A337493 (radians to arcminutes).
Sequence in context: A335790 A078991 A346790 * A021833 A196072 A261883
KEYWORD
cons,nonn,easy
AUTHOR
R. J. Mathar, Oct 10 2012
STATUS
approved

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Last modified March 29 05:48 EDT 2024. Contains 371265 sequences. (Running on oeis4.)