Returns the natural logarithm of the gamma function, Γ(x).
X is the value for which you want to calculate GAMMALN.
If x is nonnumeric, GAMMALN returns the #VALUE! error value.
If x ≤ 0, GAMMALN returns the #NUM! error value.
The number e raised to the GAMMALN(i) power, where i is an integer, returns the same result as (i - 1)!.
GAMMALN is calculated as follows:
Natural logarithm of the gamma function at 4 (1.791759)