F# Collections: Initialyzing an Array Using an Expression
Another way to create an array is to provide its values using an
expression. To support this, the Array class provides a method named init.
Its signature is:
Array.init : int -> (int -> 'T) -> 'T 
Here is an example:
let yCoords = Array.init 8 (fun a -> (2 * a) + 1)