**11. PEN K11 **(Canada 2002) Find all functions such that for all

:

Here, denote the set of all nonnegative integers.

Here is the official solution file: pen11.pdf.

You can also discuss the problems here!

Posted in PEN Solutions Archive on October 29, 2008| Leave a Comment »

Posted in Problem of the Bi-Week on October 19, 2008| Leave a Comment »

Hi everyone. PEN is BACK. Here goes the first problem of the second season!

11. PEN K11 (Canada 2002) Find all functions such that for all

:

Here, denote the set of all nonnegative integers.

This problem is suggested by **Alexander Remorov** from Canada. Next week, his solution will be posted!