Determine the probability that for a positive base ten integer N drawn at random between 2 and 201 inclusively, the number N³ - 1 is expressible in the form p*q*r, where p, q and r are three distinct positive integers such that p, q and r (in this order) corresponds to three consecutive terms of an arithmetic progression.

Well, that's not the most general formal for a geometric progression, which means that the earlier solution outline might be missing solutions.

Posted by Steve Herman on 2010-06-01 01:24:43