Fibonacci in Kotlin

Fibonacci.kt

fun seriesUntilPosition(position: Int): List<Int> {
    return (1..position)
            .map { Pair(0, 1) }
            .fold(listOf(Pair(0, 1))) { acc, first ->
                val last = acc.last()
                acc + (Pair(last.second, last.first + last.second))
            }
            .map { it.second }
}

//Oppure eliminando l'uso della classe Pair
fun seriesUntilPosition(position: Int): List<Int> =
     (1..position)
          .fold(listOf(0, 1))
          { acc, _ -> acc + (acc.last() + acc[acc.lastIndex - 1]) }
          .drop(1)