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A049541
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Decimal expansion of 1/Pi.
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65
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3, 1, 8, 3, 0, 9, 8, 8, 6, 1, 8, 3, 7, 9, 0, 6, 7, 1, 5, 3, 7, 7, 6, 7, 5, 2, 6, 7, 4, 5, 0, 2, 8, 7, 2, 4, 0, 6, 8, 9, 1, 9, 2, 9, 1, 4, 8, 0, 9, 1, 2, 8, 9, 7, 4, 9, 5, 3, 3, 4, 6, 8, 8, 1, 1, 7, 7, 9, 3, 5, 9, 5, 2, 6, 8, 4, 5, 3, 0, 7, 0, 1, 8, 0, 2, 2, 7, 6, 0, 5, 5, 3, 2, 5, 0, 6, 1, 7, 1
(list; constant; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| The ratio of the volume of a regular octahedron to the volume of the circumscribed sphere (which has circumradius a*sqrt(2)/2 = a*A010503, where a is the octahedron's edge length; see MathWorld link). For similar ratios for other Platonic solids, see A165922, A165952, A165953, and A165954. [From Rick L. Shepherd (rshepherd2(AT)hotmail.com), Oct 01 2009]
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REFERENCES
| Mohammad K. Azarian, An Expression for Pi, Problem #870, College Mathematics Journal, Vol. 39, No. 1, 2008, pp. 66. Solution appeared in Vol. 40, No. 1, 2009, pp. 62-64. [From Mohammad K. Azarian (azarian(AT)evansville.edu), Feb 08 2009]
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LINKS
| J. Bohr, Ramanujan's Mathod of Approximating Pi
J. Borwein, Ramanujan's Sum
J. Guillera, A New Method to Obtain Series for 1/pi and 1/(pi)^2
R. Matsumoto, Ramanujan Type Series
Weisstein, Eric W., "Octahedron."
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EXAMPLE
| 0.3183098861837906715377675267450287240689192914809128974953...
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MATHEMATICA
| RealDigits[N[1/Pi, 6! ]][[1]] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jun 18 2009]
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PROG
| (PARI) 1/Pi \\ Charles R Greathouse IV, Jun 16 2011
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CROSSREFS
| Cf. A000796, A165922, A165952, A165953, A165954, A063723, A010503. [From Rick L. Shepherd (rshepherd2(AT)hotmail.com), Oct 01 2009]
Sequence in context: A073072 A185452 A179449 * A130300 A065451 A178148
Adjacent sequences: A049538 A049539 A049540 * A049542 A049543 A049544
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KEYWORD
| nonn,cons
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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