Template:Sequence of the Day for August 25

Intended for: August 25, 2011

Timetable

• First draft entered by Mitch Harris on August 3, 2011 ✓
• Draft reviewed by Alonso del Arte on August 21, 2011 ✓
• Draft approved by ??? on August 2?, 2011

Yesterday's SOTD * Tomorrow's SOTD

The line below marks the end of the <noinclude> ... </noinclude> section.

---

A002487: Stern’s diatomic series.

{ 0, 1, 1, 2, 1, 3, 2, 3, 1, 4, 3, 5, 2, 5, 3, 4, 1, 5, 4, 7, 3, 8, 5, 7, 2, 7, 5, 8, 3, 7, ... }

Stern’s diatomic series is defined by the recursion

a (2n) = a (n), a (2n + 1) = a (n) + a (n + 1),

with base cases

a (0) = 0, a (1) = 1

.

It magically gives, by the ratio of any two successive entries, all positive rationals exactly once. It is essentially a breadth first traversal of the ratios of the nodes in the Stern–Brocot tree.