OFFSET
0,4
LINKS
Jon E. Schoenfield, Table of n, a(n) for n = 0..448 (first 100 terms from Robert G. Wilson v)
Eric Weisstein's World of Mathematics, Factorial
MAPLE
seq(length((n)!!), n=0..19); # Zerinvary Lajos, Mar 10 2007
MATHEMATICA
LogBase10Stirling[n_] := Floor[ Log[10, 2 Pi n]/2 + n*Log[10, n/E] + Log[10, 1 + 1/(12n) + 1/(288n^2) - 139/(51840n^3) - 571/(2488320n^4) + 163879/(209018880n^5) + 5246819/(75246796800n^6)]]; (* A001163/A001164; good to at least a(1000) *) LogBase10Stirling[0] = LogBase10Stirling[1] = 0; Table[1 + LogBase10Stirling[n!], {n, 0, 101}] (* Robert G. Wilson v, Aug 05 2015 *)
PROG
(PARI) \\ Using 100 digits of precision.
a(n)=localprec(100); my(t=n!); return(floor((t*log(t)-t+1/2*log(2*Pi*t)+1/(12*t))/log(10)+1))\\ Robert Gerbicz, Jul 08 2008
(Magma) // Using about 100 more digits of precision than needed.
nMax:=30; SetDefaultRealField(RealField(Ceiling(Log(10, Factorial(nMax))+100))); a:=[]; for n in [0..nMax] do a[n+1]:=1+Floor(LogGamma(Factorial(n)+1)/Log(10)); end for; a; // Jon E. Schoenfield, Aug 07 2015
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Robert G. Wilson v, Sep 05 2001
EXTENSIONS
More terms from Vladeta Jovovic, Sep 06 2001
A correspondent reported that terms a(17) - a(19) shown here were wrong. That's not true, they are correct. The correspondent was using Python, where the default precision was not large enough to calculate these terms correctly. Thanks to Brendan McKay, Max Alekseyev and Robert Gerbicz for confirming the entries. - N. J. A. Sloane, Jul 08 2008
a(20) from Brendan McKay, Jul 08 2008
a(21)-a(22) from Hugo Pfoertner, Nov 25 2023
STATUS
approved