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A005600 Decimal expansion of reciprocal of fine-structure constant alpha.
(Formerly M2606)
1, 3, 7, 0, 3, 5, 9, 9, 9, 1 (list; constant; graph; refs; listen; history; text; internal format)



The fine-structure "constant" actually isn't a constant, it depends on the energy at which it is measured: Its value is known to approach 1/128 at interaction energies above 80 GeV. For other considerations, e.g., whether the value of the fine-structure constant differs by location and over time, see the Wikipedia article or other links. - M. F. Hasler, Oct 30 2013


John Barrow, The Constants of Nature, 367 pp., Jonathan Cape, 2002.

K. R. Lang, Astrophysical Data: Planets and Stars, Springer-Verlag, NY, 1991.

Martin J. Rees, Just Six Numbers: the deep forces that shape the universe, Phoenix, 1999.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


Table of n, a(n) for n=3..12.

E. R. Cohen and B. N. Taylor, The 1986 adjustment of the fundamental physical constants, Rev. Modern Phys., 59 (1987), 1121-1148.

NIST, inverse fine-structure constant

Robert P. Munafo, Notable Properties of Specific Numbers. [From Robert G. Wilson v, Sep 10 2008]

Wikipedia, Fine-structure constant


1/alpha = 1/A003673.

1/alpha = c/V_n1 = A003678/A081800. - Omar E. Pol, Mar 11 2018




Cf. A003673, A082726.

Sequence in context: A127584 A124919 A033920 * A180873 A021031 A291835

Adjacent sequences:  A005597 A005598 A005599 * A005601 A005602 A005603




N. J. A. Sloane, Mira Bernstein


Updated May 20 2003

Updated by Omar E. Pol, Aug 09 2009, by Raphie Frank, Dec 13 2012

Updated by Arkadiusz Wesolowski, Feb 08 2016



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Last modified December 8 18:37 EST 2019. Contains 329865 sequences. (Running on oeis4.)