help rewriting in functional style

Question

I\'m learning Scala as my first functional-ish language. As one of the problems, I was trying to find a functional way of generating the sequence S up to n places. S is defined

Answer 1

The following code produces exactly the same sequence as yours:

val seq = Stream.from(1)
        .flatMap(Stream.fill(2)(_))
        .zipWithIndex
        .flatMap(p => Stream.fill(p._1)(p._2))
        .tail

However, if you want to produce the Golomb sequence (that complies with the definition, but differs from your sample code result), you may use the following:

val seq = 1 #:: a(2)
def a(n: Int): Stream[Int] = (1 + seq(n - seq(seq(n - 2) - 1) - 1)) #:: a(n + 1)

You may check my article for more examples of how to deal with number sequences in functional style.