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A156057
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Decimal expansion of log(3)/2.
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2
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5, 4, 9, 3, 0, 6, 1, 4, 4, 3, 3, 4, 0, 5, 4, 8, 4, 5, 6, 9, 7, 6, 2, 2, 6, 1, 8, 4, 6, 1, 2, 6, 2, 8, 5, 2, 3, 2, 3, 7, 4, 5, 2, 7, 8, 9, 1, 1, 3, 7, 4, 7, 2, 5, 8, 6, 7, 3, 4, 7, 1, 6, 6, 8, 1, 8, 7, 4, 7, 1, 4, 6, 6, 0, 9, 3, 0, 4, 4, 8, 3, 4, 3, 6, 8, 0, 7, 8, 7, 7, 4, 0, 6, 8, 6, 6, 0, 4, 4
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OFFSET
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0,1
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COMMENTS
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Culler & Shalen show a bound of log(3)/2 on maximal injectivity under certain circumstances, see links.
Also decimal expansion of arctanh(1/2) = arccoth(2) = integral_{x>2} 1/(x^2-1). - Jean-François Alcover, Jun 04 2013
Equals arctanh(1/2), the rapidity of an object traveling at half the speed of light. - Sean Stroud, May 13 2019
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LINKS
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Table of n, a(n) for n=0..98.
Marc Culler, Peter B. Shalen, Betti numbers and injectivity radii, Proceedings of the American Mathematical Society, Vol. 137, No. 11 (2009), pp. 3919-3922, preprint, arXiv:0902.0014 [math.GT], 2009.
Index entries for transcendental numbers
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FORMULA
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From Amiram Eldar, Aug 05 2020: (Start)
Sum_{k>=0} 1/((2*k+1) * 2^(2*k+1)).
Equals Integral_{x=0..oo} 1/(exp(x) + 2) dx. (End)
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EXAMPLE
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0.54930614433405484569762261846...
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MATHEMATICA
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RealDigits[Log[3]/2, 10, 120][[1]] (* Harvey P. Dale, Apr 13 2016 *)
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PROG
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(PARI) log(3)/2 \\ Charles R Greathouse IV, May 15 2019
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CROSSREFS
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Cf. A002391 (decimal expansion of natural logarithm of 3).
Sequence in context: A097943 A241420 A077142 * A125057 A021186 A195705
Adjacent sequences: A156054 A156055 A156056 * A156058 A156059 A156060
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KEYWORD
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nonn,cons,easy
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AUTHOR
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Jonathan Vos Post, Feb 03 2009
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EXTENSIONS
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All digits were wrong. Corrected by N. J. A. Sloane, Feb 05 2009
Offset 0 from Michel Marcus, May 13 2019
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STATUS
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approved
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