Subfactorials Explained | Full Video

In this video, i will explain what a subfactorial is and use the explanation of what a factorial is to break this down for you. Factorials focus on the arrangements whereas subfactorials focus more on dearrangements.

[michael__..]

Is there a formular, or method for doing subfactorial.
We know there's a structured way to do factorial, eg. 3! is 3×2×1=6. 100! Is 100×99×98×97×96...×1
If I have to do !50, I cannot count it out like you did in the example.

[michael__..]

One object cannot be arranged differently from how it was already arranged. It cannot be placed in the second position, or third, or fourth which would be different from how it was before.

[mr.d]

*One subfactorial will be zero because a single object can't be deranged into any other order.*