/// Fibonacci Number formula
let rec fib n =
match n with
| 0 | 1 -> n
| _ -> fib (n - 1) + fib (n - 2)
/// Another approach - a lazy infinite sequence of Fibonacci numbers
let fibSeq = Seq.unfold (fun (a,b) -> Some(a+b, (b, a+b))) (0,1)
// Print even fibs
[1 .. 10]
|> List.map fib
|> List.filter (fun n -> (n % 2) = 0)
|> printList
// Same thing, using a list expression
[ for i in 1..10 do
let r = fib i
if r % 2 = 0 then yield r ]
|> printList