4,2

The estimate is continually changing.

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

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

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

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

NIST, Constants, Units and Uncertainty

1836.15...

Cf. A003677.

Sequence in context: A019728 A113476 A124599 this_sequence A104697 A010522 A132035

Adjacent sequences: A005598 A005599 A005600 this_sequence A005602 A005603 A005604

cons,nonn,nice,hard

N. J. A. Sloane (njas(AT)research.att.com).