What are the possible values of a six digit positive integer N, where all digits of N are different, and 4*N has the same six digits as N?
Prove that there are no others.
(In reply to Let me count the ways
by Steve Herman)
Have reviewed Charlie's list, I see that my assertion that N = 0 mod 9 was incorrect.
N can also = 3 or 6 mod 9.
So the total number of viable candidates was about 6,720, about three times what I thought.
64, a little less that 1% of these, actually worked.