where is Knuth's (1976) Arrow Notation.

The infinite power tower converges Iff ( ).

**References**

Knuth, D. E. ``Mathematics and Computer Science: Coping with Finiteness. Advances in our Ability to Compute are
Bringing us Substantially Closer to Ultimate Limitations.'' *Science* **194** 1235-1242, 1976.

Vardi, I. *Computational Recreations in Mathematica.* Reading, MA: Addison-Wesley, pp. 11 and 226-229, 1991.

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1999-05-26