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This function returns the natural logarithm of the Gamma function, G(x).
GAMMALN(value)
[Required] The argument is any numeric value.
This function is calculated as the natural logarithm (LN) of the Gamma function.
The equation for this function is:

where x is the value argument.
GAMMALN(A4)
GAMMALN(R4C1)
GAMMALN(12) gives the result 17.5023078459