{75, 100, 125} is an example of an arithmetic progression of positive integers such that the n-th term is a perfect n-th power.
Find a longer sequence with this feature.

What is the longest you can get?
P.S. Trival solution(d=0) excluded.

(In reply to Further conditions? by ed bottemiller)

Ed,

I believe the 'n-th' term is referring to the 1st, 2nd, and 3rd terms being 1st, 2nd, and 3rd perfect powers. 75 = 75^1, 100 = 10^2, 125 = 5^3.

Posted by Justin on 2010-07-22 14:48:20