Template:Sequence of the Day for January 11

Intended for: January 11, 2013

Timetable

• First draft entered by M. F. Hasler on January 3, 2013 ✓
• Draft reviewed by Alonso del Arte on January 3, 2013 ✓
• Draft approved by Charles R Greathouse IV on January 3, 2013 ✓

Yesterday's SOTD * Tomorrow's SOTD

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

---

A130111: Rearrangement* of natural numbers such that each five terms sum up to a perfect square.

{ 1, 2, 3, 4, 6, 5, 7, 8, 9, 20, 10, 11, 12, 13, 18, 14, 15, 16, 17, 19, 21, 22, 23, 24, 31, ... }

To be precise, one should also specify explicitly that the smallest possible choice is to be made for each

a (n), n = 1, 2, 3, ...

(i.e., the lexicographically smallest sequence), which is often tacitly understood in such cases.

_______________
* “Rearrangement” means that every natural number appears and no number can occur twice.