Seeks the minimum number of checkers placed on a board required to allow pieces to move by a sequence of horizontal or vertical jumps (removing the piece jumped over) rows beyond the forward-most initial checker. The first few cases are 2, 4, 8, 20. It is, however, impossible to reach level 5.

**References**

Honsberger, R. *Mathematical Gems II.* Washington, DC: Math. Assoc. Amer., pp. 23-28, 1976.

© 1996-9

1999-05-26