# Scientific Calculator

### Scripts tagged enumerative combinatorics

- bthiessen/factorial2
written by bthiessen
Double Factorial: Factorial function which only considers integers in the sequence of same parity (6!! = 6 x 4 x 2)

- bthiessen/subfactorial
written by bthiessen
Subfactorial: (derangement) permutation of the elements of a set, such that no element appears in its original position