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Denominators of an asymptotic series for the factorial function.
3

%I #11 Sep 23 2016 12:25:07

%S 1,24,80,45360,14869008,1809260919664,1893786570223344344811120,

%T 434929389096410771976850108581894819120,

%U 842034816645697476736023674501481289989461304853979754032,12493081332932849693690211275701739272086387015742438665176379932658393033468667344

%N Denominators of an asymptotic series for the factorial function.

%C C_n = A182914(n)/A182915(n). These rational numbers provide the coefficients for an asymptotic expansion of the factorial function.

%H L. Feng and W. Wang, <a href="http://dx.doi.org/10.1007/s11075-012-9671-x">Two families of approximations for the gamma function</a>, Numerical Algorithms, Springer 2012.

%H Peter Luschny, <a href="https://oeis.org/wiki/User:Peter_Luschny/FactorialFunction">Approximations to the factorial function</a>.

%H W. Wang, <a href="http://dx.doi.org/10.1016/j.jnt.2015.12.016">Unified approaches to the approximations of the gamma function</a>, J. Number Theory (2016).

%F Let N = n + 1/2 and p = N^2*C_0/(N+C_1/(N+C_2/(N+C_3/(N+C_4/N)...))), then

%F n! ~ sqrt(2Pi) (p/e)^N.

%e C_0 = 1, C_1 = 1/24, C_2 = 3/80, C_3 = 18029/45360, C_4 = 6272051/14869008.

%Y Cf. A182914 (numerators).

%K nonn,frac

%O 0,2

%A _Peter Luschny_, Mar 08 2011