OFFSET
1,2
COMMENTS
The 5th root r(5) of the expected value E(|x|^5) for a normal distribution with zero mean and standard deviation 1. See A289090 for more details.
LINKS
Stanislav Sykora, Table of n, a(n) for n = 1..1000
Wikipedia, Normal distribution.
FORMULA
Equals r(5), where r(p) = ((p-1)!!*sqrt(2/Pi))^(1/p).
Equals (8*A076668)^(1/5).
EXAMPLE
1.44879190154930528525354659881281058821340103935196780729503058015...
MATHEMATICA
RealDigits[(8*Sqrt[2/Pi])^(1/5), 10, 120][[1]] (* Amiram Eldar, Mar 22 2026 *)
PROG
(PARI) \\ General code, for any p > 0:
r(p) = (sqrt(2/Pi)^(p%2)*prod(k=0, (p-2)\2, p-1-2*k))^(1/p);
a = r(5) \\ Present instance
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Stanislav Sykora, Jul 26 2017
STATUS
approved
