range

In std/seq.

fn range(start: Int, end: Int, step: Int = 1) : List<Int>

The Ints from start up to, not including, end, each step after the one before: range(1, 6) is [1, 2, 3, 4, 5], and range(10, 0, -3) is [10, 7, 4, 1].