[seqfan] A sequence from Johannes Kepler's "Harmonices Mundi"

[Peter Luschny]

We all know Stern-Brocot, Dijkstra, and the Calkin and Wilf tree.
David Eppstein posted today on G+ this picture [0].

And Eppstein added to Wikipedia: "Even earlier, a similar tree appears in
Johannes Kepler's "Harmonices Mundi" (1619, volume=III, page=27)." [1]

Hope you like it as much as I do.

Peter

[0] http://www.ics.uci.edu/~eppstein/0xDE/CalkinWilfKepler.png
[1] https://archive.org/stream/ioanniskepplerih00kepl#page/27/mode/1up
[2] https://oeis.org/A002487