User blog comment:LittlePeng9/ITTM galore/@comment-24509095-20140326102311/@comment-10429372-20140326130341

For ω^2, I think that we could use this:

1, 2, 4, 6, 8, ...., 3, 9, 15, 21, ..., 5, 25, 45, ...., 7, 49, ...., ....