Quote:
Originally Posted by LaurV
Neee.. gotcha! (so long I waited for that! )
r must be prime, I guess you didn't know that 1 is not considered a prime

Fairy Nuff: I overlooked that condition.
OK, choose r=2. Prime, right?
Let b=17, so B^2100r = 289200 = 89 = a. All are positive and coprime.
Let b=19, so b^2100r = 361200 = 161 = 7 * 23 = a. All are positive and coprime.
Let b=21, so a=241 which is a prime.
And so on.
It is still a trivial problem.