I am impressed with this latter response. The 2 digit multiplicand and its multiplier have no repeat digits and the product increments by 4.

In the second offer your AP increment is 5 but I must point out that in the third your 4th term [114 is the product of 4*28.5].

There is just one other thing, I asked for a sequence having the lowest initial multiplicand.
 
I do have a 6 term series where 20 is the lowest multiplicand.



[As an aside I see that with collaboration it might have been possible to generate a short series around the basic concepts here.]

Posted by brianjn on 2013-02-04 01:56:08