OFFSET
1,1
FORMULA
Equals limit n->infinity (Product_{k=0..n} (k^4)!) / (n^(1 + 28*n/15 + 4*n^3/3 + 2*n^4 + 4*n^5/5) * (2*Pi)^(n/2) / exp(19*n/9 + n^4/2 + 9*n^5/25)).
Equals 2*Pi*exp(-3*Zeta(5)/Pi^4) * Product_{n>=1} ((n^4)!/stirling(n^4)), where stirling(n^4) = sqrt(2*Pi) * n^(4*n^4 + 2) / exp(n^4) is the Stirling approximation of (n^4)! and Zeta(5) = A013663. - Vaclav Kotesovec, Apr 20 2016
EXAMPLE
6.644987918706354049483118316737842660075362652005201561326290428710371...
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Vaclav Kotesovec, Feb 24 2015
STATUS
approved