F# で Project Euler Problem 15

> ([21..40] |> List.reduce(*)) / ([1..20] |> List.reduce(*))
- ;;
val it : int = 0
> ([21I..40I] |> List.reduce(*)) / ([1I..20I] |> List.reduce(*))
- ;;
val it : System.Numerics.BigInteger = 137846528820I