## More Christmas Math!

by

I posted recently about Christmas math, but in digging around it turns out that there is more out there than I’d realized (and I also found a Hanukkah Math Song, so check back Dec 21, 2008!). Here are some more Christmas math tidbits, including one from the TV series Futurama:

• There’s the Christmas Stocking Theorem (also called the hockey puck theorem) which references a pattern in Pascal’s Triangle.
• Apparently there’s a whole slew of items you can buy that say $HO^3$ for the mathematicians in your life. Or you could just ask them “What’s purple, round, and doesn’t get much for Christmas?”*
• The blog Let’s play math! has a post on Christmas math puzzles and activities with interesting links geared towards younger mathematicians.
• And finally, in Season 2 of Futurama, Bender gets a card which reads MERRY XMAS SON #1729 (see screen shot here). The number 1729 was made famous by a story that G. H. Hardy told about Srinivasa Ramanujan in his book Ramanujan (published in 1940):

I remember once going to see him when he was lying ill at Putney. I had ridden in taxi cab number 1729 and remarked that the number seemed to me rather a dull one, and that I hoped it was not an unfavorable omen. “No,” he replied, “it is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways.”

(1729 can be written as $1^3 + 12^3$ or as $9^3 + 10^3$.)

As an aside, in the recent movie Bender’s Big Score the number on the taxicab is 87539319, which can be expressed as the sum of two cubes in three different ways: $167^3 + 436^3,$ $228^3 + 423^3,$ or $255^3 + 414^3.$ (Check out The Geekiest Show on TV from Wired Magazine.)

Enjoy!

* A finitely presented grape.