The expansion of the two sides of a sum equality in terms of Polynomials in and , followed by closed form summation in terms of and . For an example of the technique, see Bloom (1995).

**References**

Bloom, D. M. ``A Semi-Unfriendly Identity.'' Problem 10206. Solution by R. J. Chapman. *Amer. Math. Monthly* **102**, 657-658, 1995.

Wilf, H. S. *Generatingfunctionology, 2nd ed.* New York: Academic Press, 1993.

© 1996-9

1999-05-26