F# solution to Project Euler 31

pe32.fs

module PE31

let solution n = 
    let filter_less_than n = List.filter (fun c -> c <= n)
    let rec _solution values = function
        | 200 -> 1 // success
        | n when n > 200 -> 0
        | n ->  List.sum (List.map (fun coin -> _solution (values |> filter_less_than coin) (n + coin)) values)
    _solution [200; 100; 50; 20; 10; 5; 2; 1] n

// run
solution 0