OFFSET
0,1
COMMENTS
Sometimes called the Omega constant.
Infinite power tower for c = 1/E, i.e., c^c^c^..., where c = 1/A068985. - Stanislav Sykora, Nov 03 2013
Notice the narrow interval exp(-gamma) < w(1) < gamma, with gamma = A001620. - Jean-François Alcover, Dec 18 2013
Also the solution to x = -log(x). - Robert G. Wilson v, Feb 22 2014
LINKS
G. C. Greubel and Stanislav Sykora, Table of n, a(n) for n = 0..10000 (terms 0..1999 from Stanislav Sykora)
Mateus Araújo, Andrew J. P. Garner, and Miguel Navascues, Non-commutative optimization problems with differential constraints, arXiv:2408.02572 [quant-ph], 2024. See p. 13.
blackpenredpen, Finding Omega, featuring Newton's method, video (2018).
Daniel Cummerow, Sound of Mathematics, Constants.
István Mező, An integral representation for the Lambert W function, arXiv:2012.02480 [math.CA], 2020.
Simon Plouffe, Lambert W(1, 0).
Simon Plouffe, The omega constant or W(1).
Stanislav Sykora, Fixed points of the mappings exp(z) and -exp(z) in C, Stan's Library, Vol. VI, 2016.
Eric Weisstein's World of Mathematics, Omega Constant.
Eric Weisstein's World of Mathematics, Lambert W-Function.
Wikipedia, Omega constant.
Wadim Zudilin, Diophantine problems related to the Omega constant, arXiv:2004.11029 [math.NT], 2020.
FORMULA
Equals 1/A030797.
Equals (1/Pi) * Integral_{x=0..Pi} log(1 + sin(x)*exp(x*cot(x))/x) dx (Mező, 2020). - Amiram Eldar, Jul 04 2021
EXAMPLE
0.5671432904097838729999686622103555497538157871865125081351310792230457930866...
MAPLE
evalf(LambertW(1));
MATHEMATICA
RealDigits[ ProductLog[1], 10, 111][[1]] (* Robert G. Wilson v, May 19 2004 *)
PROG
(PARI) solve(x=0, 1, x*exp(x)-1) \\ Charles R Greathouse IV, Mar 20 2012
(PARI) lambertw(1) \\ Stanislav Sykora, Nov 03 2013
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
STATUS
approved