Tail recursive Fibonacci Sequence

gistfile1.fs

open System

// Tail recursive Fibonacci
// BigInt -> BigInt
let bigFib n =
    let rec loop previous previousPrevious = function
        | n when n = 0I -> previousPrevious
        | n -> loop (previous + previousPrevious) previous (n - 1I)
    loop 1I 0I n
            
 
let main() =
    [0I .. 100I] |> Seq.iter (fun x -> printfn "fib(%O) = %O" x (bigFib x))

    Console.ReadKey() |> ignore
 
main()