Density Map for the 3n+1 Problem
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Start with a number and repeat: if is even, halve it; if is odd, triple it and add one. For example, starting with 3 gives 3, 10, 5, 16, 8, 4, 2, 1. Rearrange the numbers in ascending order and mark those places across row so that the third row has marks at the places 1, 2, 3, 4, 5, 10, 16.
Contributed by: Michael Schreiber (March 2011)
Open content licensed under CC BY-NC-SA
"Density Map for the 3n+1 Problem"
Wolfram Demonstrations Project
Published: March 7 2011