A game played with two heaps of counters in which a player may take any number from either heap or the same number from both. The player taking the last counter wins. The th Safe combination is , where , with the Golden Ratio and the Floor Function. It is also true that . The first few Safe combinations are (1, 2), (3, 5), (4, 7), (6, 10), ....

**References**

Ball, W. W. R. and Coxeter, H. S. M. *Mathematical Recreations and Essays, 13th ed.*
New York: Dover, pp. 39-40, 1987.

Coxeter, H. S. M. ``The Golden Section, Phyllotaxis, and Wythoff's Game.'' *Scripta Math.* **19**, 135-143, 1953.

O'Beirne, T. H. *Puzzles and Paradoxes.* Oxford, England: Oxford University Press, pp. 109 and 134-138, 1965.

© 1996-9

1999-05-26