Function Repository Resource:

# InverseFactorial

Compute the inverse factorial of a strictly positive integer by solving the gamma function for a specific value

Contributed by: Peter Cullen Burbery
 ResourceFunction["InverseFactorial"][n] computes the inverse factorial of the positive integer n.

## Details

The input should be in the set ={1,2,3,} of natural numbers.

## Examples

### Basic Examples (2)

Find the inverse factorial of 24:

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### Scope (3)

InverseFactorial can compute results for inputs that are not factorials of integers:

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Find the inverse factorial of 403:

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Find the inverse factorial of 2022:

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Find the numerical value to 1000 digits:

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### Possible Issues (2)

The function only accepts integers:

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The argument must be greater than 0:

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Peter Burbery

## Version History

• 1.0.0 – 29 August 2022