Nice. Surprised they don't mention that under relations for Permutations.

@Rojo Thanks

Even W|A just says you inputted n!/(n-k)! when you feed it P(n,k)

:)

I think I'm actually gonna write to them about it. I can't be the only one who found their documentation lacking in this regard.

Oh never mind, I'm just blind and didn't see it there.

I still think FactorialPower is an awful name but whatever

Since my computer broke down, and I'm now using a different one, I have to look up stuff to be able to access PackageData which is why I haven't had the energy to fix the issue with spam in the RSS yet, but it's coming.

@Pavel It's not an awful name and makes perfect sense. Look at the first line of the documentation: FactorialPower[x,n] give the factorial power x^(n). Now if one only knew it in the form n!/(n-k)!, then I agree it wouldn't make sense. Sometimes it's called a "round power" (because of the parentheses).

Unfortunately the notation isn't consistent those of rising and falling factorials: en.wikipedia.org/wiki/Falling_and_rising_factorials.

@MichaelHale My small piece of respect to Mr. Conway. If you (or anyone) try the code, you will see none of the "spheres" are spheres.

@C.E. Question about PackageData: Suppose there's a package entry. A spammer comes along and edits it. The edit is in the review queue. I click "Move To Trash". This will only reject the edit, right? It will not delete the original entry.

@Szabolcs This is correct. It will only reject the suggested edit.

When dividing with the column index "k" and taking row sums one get the partial sums of the Möbius inverse of the Harmonic numbers minus "n".

*gets

@Silvia Longest game of life style cycle on a dodecahedron (two red neighbours required for a red pentagon).

Well, there are other rules with a cycle length eight, but not longer.

@Silvia Wow, very cool. Very professional final graphics. Could see it as an actual object in a museum. Random note about notebook format. I guess hiding the cell brackets makes the final publish better, but did make it harder for me to tell what cells I had selected and evaluated. Had to google how to show them again haha. Had forgotten about option inspector.