Sieve.fs

let rec sieve (xs : int seq) = 
    seq {
      let p = xs |> Seq.take 1 |> Seq.exactlyOne 
      yield p
      yield! xs |> Seq.skip 1 |> Seq.filter (fun x -> x % p <> 0) |> sieve
    }
  
let ints = Seq.initInfinite (fun x -> x + 2)
let primes = sieve ints

Note: This is not the genuine Sieve of Eratosthenes but rather the inefficient naive sieve.

See http://www.cs.hmc.edu/~oneill/papers/Sieve-JFP.pdf for details.