[math-fun] A different fun function

This sounds like an enumeration of the nodes in a Stern-Brocot tree: http://www.cut-the-knot.org/blue/Stern.shtml http://en.wikipedia.org/wiki/Stern%E2%80%93Brocot_tree Tom Allan Wechsler writes:

Steve Witham's function reminded me that I have never learned the name of the following function, similar in some ways to Steve's example, but closely related to Farey sequences and continued fractions.