Yes, you are correct, I had misinterpreted the test results and misread that aspect of the instructions. Apologies if I waylaid anyone and thanks for catching it.

I see now - incrementing sequences can END in a zero but it can't wrap around.

I would edit this issue but I don't think I can once marked solved.

So 7890 is interesting but 7891 isn't.

Edit - ok, i'm seeing it more clearly... it doesn't wrap around but it can end it zero .I'll edit my response

Edit -

My response here was incorrect as per the instructions. 109 should not be considered interesting because decrementing sequences shouldn't wrap around.

Both 7473747 and 1221 are palindromes - what's the issue?

I don't know what the 11209 one was, but 99 should return 1 because 99+1 == 100, an interesting number.

Done in Java. Only thing that slowed me down was merging the minor array in an efficient way. Used the Arrays utility to do it, but I suppose I could have iterated it better from the get-go.

Is there a more efficient way to do it than recursion?