OFFSET
1,2
COMMENTS
Also 8th root of 9. - Alonso del Arte, Dec 06 2011
The 4th root r(4) of the expected value E(x^4) for a normal distribution with zero mean and standard deviation 1. See A289090 for more details. - Stanislav Sykora, Jul 26 2017
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..5000
Amrik Singh Nimbran, Interesting infinite products of rational functions motivated by Euler, Math. Student, Vol. 85 (2016), pp. 117-133; ResearchGate link.
FORMULA
Equals exp(arctanh(1/2)/2). - Amiram Eldar, Jul 10 2023
From Amiram Eldar, Jun 28 2026: (Start)
Equals Product_{k>=1} (12*k-8)^2*(12*k-7)/((12*k-9)^2*(12*k-5)) (Nimbran, 2016, p. 130, eq. (50)).
Equals Product_{k>=1} (3*k-1)*(4*k-2)^2*(12*k-5)/((3*k-2)*(4*k-1)^2*(12*k-7)) (Nimbran, 2016, p. 130, eq. (51)). (End)
EXAMPLE
1.3160740129524924608192189...
MATHEMATICA
RealDigits[3^(1/4), 10, 100][[1]]
PROG
(PARI) sqrtn(3, 4) \\ Charles R Greathouse IV, Apr 14 2014
CROSSREFS
KEYWORD
AUTHOR
STATUS
approved
