I solved the 3rd sequence of step 4!
321, 444, 675, 680, 370, 268, 949, 206, 851, ?, ...
You have to consider each digit independently, like a 0 to 9 wheel. and from the first three digits you kind of weave a +1 thread a +2 thread and a +3 thread. What I mean is that each thread goes 1st...