1)Let

. Define

,

and

. Find the radius of convergence of

.
The next two problems are for the younger kids, so give them a chance.
2)Let

be a set (non-empty) of finite terms. A "partition" is breaking the set into two sets (non-empty) so that together they have the all the elements of

but none of eachother. For example, let

then

are partitions. But

are not. Say that

has

elements. How many different paritions are there in terms of

?
3)Given an

checkerboard what is the maximum number of checkers which can be placed so that no two are adjacent.
Prove your answer. "Adjacent" means either horizontally or veritcally next to eachother
not diagnolly.