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Template:Sequence of the Day for December 25

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Intended for: December 25, 2011

Timetable

  • First draft entered by Alonso del Arte on May 28, 2011 as a verbatim copy of a write-up from December 25, 2010
  • Draft to be reviewed by October 25, 2011
  • Draft to be approved by November 25, 2011

Yesterday's SOTD * Tomorrow's SOTD

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A000292: Tetrahedral numbers.

{ 1, 4, 10, 20, 35, 56, 84, 120, 165, 220, 286, 364, ... }

On the first day of Christmas, my true love gave me a partridge in a pear tree. The next day, she gave me two turtle doves and another partridge in a pear tree. And the next day, three French hens, another two turtle doves and yet another partridge in a pear tree. By the seventh day, I had a serious storage problem.

If there was a way to encase all these gifts into small balls with a radius of half a unit, a triangular frame with each side twelve units long would be sufficient to organize all these gifts into a nice, little tetrahedron, since it just so happens that the running total of gifts received each day is a tetrahedral number. But of course the whole issue of storage is moot because the gifts are symbols of various concepts relevant to the celebration of Christmas.