In my Learning F# posts you probably saw how you can generate an int array like this:
let x = [1 .. 10];;
this returns 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
This is pretty cool, and fortunately, you have something very similarly in C# with Enumerable.Range which you can use by supplying a starting number and a count:
var x = Enumerable.Range(1, 10);