階乗進法

factorialNumberSystem.fsx

let factorialNumberSystem n =
    let n = n - 1

    let factorials =
        if n = 0 then [1]
        else
            Seq.initInfinite ((+) 2) |> Seq.scan (*) 1 |> Seq.takeWhile ((>=) n)
            |> Seq.toList |> List.rev

    let factoradic k =
        (k, factorials) |> List.unfold (function
            | _, [] -> None
            | x, f::fs -> Some(x / f, (x % f, fs)))

    [for i in 0 .. n -> factoradic i]