Anubrato Roy wrote:My take is that Ryan likes numbers where the difference of sum of the alternate digits is odd.
I would say that qualifies as "humorously correct". Yes, I do indeed like 1024. Also, the rule you stated will correctly identify numbers I like versus the ones I don't like. However, the statement of the rule is more complicated than the one I had in mind.
If we know that the difference between two numbers is either even or odd, what can we say about the sum of those same numbers?
If two numbers have an even sum, how even numbers did we start with? How many odd?
(Addition is associative and commutative.)
Is there a simpler rule that is equivalent to the "odd difference of sums of alternate digits" one given above?