open System

open FSharpx.Control

​

let rec numbers n x = asyncSeq {

    yield n

    //printfn "%A" n

    do! Async.Sleep(1)

    if (n + 1 = x) then

        yield n + 1

    else

        yield! numbers (n + 1) x

}

​

Async.Sleep(300) |> Async.RunSynchronously

for i in [0..300] do printfn "%A" i

numbers 0 300

|> AsyncSeq.iter (fun x -> printfn "%A" x)

|> Async.RunSynchronously