Formula for the number of derangement of a derangement? - Quora
Subfactorial -- from Wolfram MathWorld
soft question - Does double subfactorial exist? - Mathematics Stack Exchange
Derangement - Wikipedia
Derangement - Wikipedia
subfactorial & derangement, an explicit approach - YouTube
Subfactorial - Statistics How To
Mathematical Meanderings: Subfactorials, Semifactorials and Others
Extra-math - 🔸️Primorial & Alternating Factorial | Facebook
4 = Sub-factorial (DERANGEMENT) I Learn Left-factorial or Sub-factorial - YouTube
Mathematical Meanderings: Subfactorials, Semifactorials and Others
javascript - Why is my subfactorial function off by one? - Stack Overflow
1. Recall that ni (called subfactorial) is the number | Chegg.com
Solved . Recall that ni (called subfactorial) is the number | Chegg.com
code golf - Deranged !Combinatorics: Compute the Subfactorial - Code Golf Stack Exchange
Derangement Formula Proof | PDF | Permutation | Recurrence Relation
Stats Calculator Free for Android - Download | Bazaar
Subfactorial / X
Factorial Calculator – Apps no Google Play
Subfactorial Formula | Left Factorial | Factorial - YouTube
Subfactorials — Another twist on Factorials | by Jaken Herman | Medium
Subfactorial -- from Wolfram MathWorld
Maths Ed X પર: "The 265th, or subfactorial 6-th (!6-th) day of the year. There are 265 derangements of 6 objects: 265 ways 6 objects can be arranged so no object is
