Seq Active Pattern

let (|Seq|_|) (xs:'T seq) (ys:'T seq) =
   if Seq.forall2 (=) xs ys then Some(ys |> Seq.skip (Seq.length xs))
   else None

let xs = [1..10]
match xs with
| Seq [1;2;3] ys -> ys
| _ -> failwith ""
// val it : seq<int> = seq [4; 5; 6; 7; ...]