A Matrix with 0 Determinant whose Determinant becomes Nonzero when any element on or below the
diagonal is changed from 0 to 1. An example is

There are minimal Special Matrices of size .

**References**

Knuth, D. E. ``Problem 10470.'' *Amer. Math. Monthly* **102**, 655, 1995.

© 1996-9

1999-05-26