F# doesn't have an in-built iterate function, but found an equivalent on the F# Snippets site -- http://fssnip.net/18 http://fssnip.net/18. let rec iterate

F# doesn't have an in-built iterate function, but found an equivalent on the F# Snippets site -- http://fssnip.net/18 http://fssnip.net/18. let rec iterate f value = seq { yield value yield! iterate f (f value) } Using the above we get ... let pascal = iterate (fun xs -> List.map2 (+) (0::xs) (xs @ [0])) [1]