login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A230458 Decimal expansion of Δν_{Cs} in unit s^{-1}; one of the seven units of the 2019 SI system. 13
9, 1, 9, 2, 6, 3, 1, 7, 7, 0 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
10,1
COMMENTS
The second s is defined to be exactly 9192631770 periods of the resonance frequency of the hyperfine transition of the cesium 133 atom.
Prime factors of this number are 2^1, 3^2, 5^1, 7^2, 47^1, 44351^1. - John W. Nicholson, Jun 15 2014
The value was fixed in 1968 by the 13th CGPM in terms of periods of the radiation due to the transition between the two hyperfine levels of the ground state of 133Cs atoms. - Stanislav Sykora, Mar 30 2015
In the 2019 SI system of units (see the BIPM link, and A322415) one of the seven units is Δν_{Cs} = Δν(^{133}Cs)_{hfs} = 9192631770 s^{-1}. - Wolfdieter Lang, Feb 12 2019
LINKS
Bureau International des Poids et Mesures, Unit of time (second)
W. M. Itano and N. F. Ramsey, Accurate measurement of time, Scientific American, 269 (July 1993), 56-65.
N. F. Ramsey, Precise measurement of time, American Scientist, 76 (No. 1, 1988), 42-49.
Wikipedia, Second
FORMULA
Δν_{Cs} = 9192631770 s^{-1}.
EXAMPLE
c = 9192631770 m/s.
MATHEMATICA
IntegerDigits@ 9192631770 (* Michael De Vlieger, Mar 30 2015 *)
CROSSREFS
Cf. A003678 (c), A003676 (h), A081823 (e), A070063 (k), A322578 (N_A), A244823, A322415.
Sequence in context: A339354 A280375 A067617 * A246687 A021525 A297013
KEYWORD
nonn,cons,fini,full
AUTHOR
N. J. A. Sloane, Oct 19 2013
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 19 04:26 EDT 2024. Contains 370952 sequences. (Running on oeis4.)