pub fn perm(base: u64, numbers: u64) -> StrResult<i64>Expand description
Calculates a permutation.
Returns the k-permutation of n, or the number of ways to choose k
items from a set of n with regard to order.
$ "perm"(n, k) &= n!/((n - k)!) \
"perm"(5, 3) &= #calc.perm(5, 3) $