Define an n-bloop to be any set of any n disjoint geometric circles (of possibly unequal radii) in the plane. If B is an n-bloop, then by continuously varying the centers and radii of its circles C_k we can get a family {B_t | 0 <= t <= 1} of n-bloops with B_0 = B . . . that is, AS LONG AS at no time t do any two of the n circles of B_t intersect. If B = B(0) can be so varied to B' = B(1), we say B and B' are *equivalent*. Let f(n) be the number of equivalence classes of n-bloops. What is an expression for f(n) in closed form? (I just thought of this problem and have a quick guess, but don't know the answer at the moment.) --Dan ________________________________________________________________________________________ "Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read." --Groucho Marx