REBOL [ Title: "Collatz Sequences" Date: 2010-02-25 File: %collatz.r Purpose: "Calculate collatz series, change start value and run." Library: [ level: 'beginner platform: 'all type: [one-liner] domain: [math] tested-under: none license: 'public-domain ] ] i: 100000000001 forever [either odd? i [i: i * 3 + 1] [i: i / 2] prin [i tab]]