Today I ran across an interesting paper. It gives a simple recurrence relationship to generate the elements of first n rows of a Stern-Brocot tree.
It’s surprisingly simple. To generate the first n+1 rows, take the values
where
given
where
for odd j and non-negative vi.
Put informally, vi is the number of trailing zeroes in the binary representation of i.
What’s surprising about this sequence is that it produces a list that is rational, increasing and unique.