Problem of the Week 1157
Add Plus And Add
Start with a number written in base two (e.g.,
Starting with 7423, how quickly can you get to 1?
The general question, where the starting value is arbitrary, is more difficult. And results are known when base 2 is replaced by other bases.
Source: Fall 2011 MSRI Emissary newsletter puzzle column by Joe Buhler and Elwyn Berlekamp; problem due to Gregory Galperin.
© Copyright 2012 Stan Wagon. Reproduced with permission.
16 October2 2012