An arrangement of close-packed Hexagons containing the numbers 1, 2, ..., , where is the th Hex Number, such that the numbers along each straight line add up to the same sum. In the above magic hexagon, each line (those of lengths 3, 4, and 5) adds up to 38. This is the only magic hexagon of the counting numbers for any size hexagon. It was discovered by C. W. Adams, who worked on the problem from 1910 to 1957.

**References**

Beeler, M.; Gosper, R. W.; and Schroeppel, R. *HAKMEM.* Cambridge, MA: MIT
Artificial Intelligence Laboratory, Memo AIM-239, Item 49, Feb. 1972.

Gardner, M. ``Permutations and Paradoxes in Combinatorial Mathematics.'' *Sci. Amer.* **209**, 112-119, Aug. 1963.

Honsberger, R. *Mathematical Gems I.* Washington, DC: Math. Assoc. Amer., pp. 69-76, 1973.

Madachy, J. S. *Madachy's Mathematical Recreations.* New York: Dover, pp. 100-101, 1979.

© 1996-9

1999-05-26