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A091723 Decimal expansion of the root x of Ei(x)=0, where Ei is the exponential integral. 5
3, 7, 2, 5, 0, 7, 4, 1, 0, 7, 8, 1, 3, 6, 6, 6, 3, 4, 4, 6, 1, 9, 9, 1, 8, 6, 6, 5, 8, 0, 1, 1, 9, 1, 3, 3, 5, 3, 5, 6, 8, 9, 4, 9, 7, 7, 7, 1, 6, 5, 4, 0, 5, 1, 5, 5, 5, 6, 5, 7, 4, 3, 5, 2, 4, 2, 2, 0, 0, 1, 2, 0, 6, 3, 6, 2, 0, 1, 8, 5, 4, 3, 8, 4, 9, 2, 6, 0, 4, 9, 9, 5, 1, 5, 4, 8, 9, 4, 2, 3, 9, 2 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
0,1
LINKS
Eric Weisstein's World of Mathematics, Exponential Integral.
FORMULA
Equals log(A070769). - Amiram Eldar, Aug 14 2020
Equals root x of li(exp(x)/x)=0 where li(x) is the logarithmic integral. - Artur Jasinski, Apr 19 2022
EXAMPLE
0.372507410781366634461991866580119133535689497771654...
MATHEMATICA
RealDigits[ x /. FindRoot[ ExpIntegralEi[x] == 0, {x, 1}, WorkingPrecision -> 102]][[1]] (* Jean-François Alcover, Oct 29 2012 *)
RealDigits[x /. FindRoot[LogIntegral[Exp[x]]/x, {x, 1/3}, WorkingPrecision -> 105]][[1]] (* Artur Jasinski, Apr 19 2022 *)
PROG
(PARI) solve(x=.3, 1, real(eint1(-x))) \\ Charles R Greathouse IV, Apr 14 2014
CROSSREFS
Sequence in context: A064824 A336893 A226521 * A274509 A016618 A130789
KEYWORD
nonn,cons
AUTHOR
Eric W. Weisstein, Feb 01 2004
STATUS
approved

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Last modified March 19 03:33 EDT 2024. Contains 370952 sequences. (Running on oeis4.)