OFFSET
0,1
COMMENTS
The amount of time that a customer has to wait for his order at some restaurant is a random variable having an exponential distribution with a mean of x minutes. The probability that the waiting time will be x/2 minutes or less is 1 - 1/e^(1/2).
FORMULA
Equals Integral_{x = 0..1/2} exp(-x) dx.
From Amiram Eldar, Aug 24 2020: (Start)
Equals Sum_{k>=1) (-1)^(k+1)/(2^k * k!).
Equals 1 - A092605. (End)
EXAMPLE
0.3934693402873665763962004650088195465580818645128130443171078412649434...
MATHEMATICA
RealDigits[N[1 - 1/E^(1/2), 105]][[1]]
PROG
(Magma) SetDefaultRealField(RealField(105)); n:=1-Exp(-1)^(1/2); Reverse(Intseq(Floor(10^105*n)));
(PARI) 1-exp(-1)^(1/2)
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Arkadiusz Wesolowski, Aug 04 2017
STATUS
approved