Accessing List from CSharp

I wanted to pass List from C# to F#.

I created this simple module.

(The pipes caracters are not printed !!)

namespace FSLIB

module Module =


    let rec factorial n =
        match n with
        0 -> 1
        n -> n * factorial (n - 1)

    let factFromList (n : #seq<int>) =
        let l = List.ofSeq n
        let rec fact lst =
            match lst with
            [] -> 1
            h :: t -> h * fact t
        fact l

    let rangeN a b =
        [a..b] > List.toSeq

and here is how I use it from C#

using FSLIB;

namespace TestFSLIB
{
    class Program
    {
        static void Main(string[] args)
        {
            var n = Module.factorial(5);
            List<int> lst = new List<int>(Module.rangeN(1,10));
            var fact10 = Module.factFromList(lst);
            Console.Write(fact10);
            Console.ReadLine();
      
        }
    }
}