## Friday, January 2, 2009

### Odds and Evens - First Week of 2009

The end of 2008 and the beginning of a new year has ushered in many excellent posts from some of the top math bloggers out there.

1. I plead guilty to an error of omission -- not contributing to the 46th Carnival of Mathematics over at Mike's Walking Randomly. Then again I've missed the last several so I need to make another New Year's "Re-Solution"! Mike did an excellent job of putting together the last Carnival of the year. In particular, he featured his own choices for articles for each month of the year, introducing readers to some excellent sites. Great job, Mike.

2. Naturally, the new calendar year has sparked a flurry of posts about the number 2009:
(i) The least "interesting" such post, "Get Ready for Happy 41*7^2" was probably mine.
(ii) This was followed in quick order by Mike again with his "What is interesting about the number 2009?" post over at Walking Randomly. Mike suggested representing 2009 as sums of powers leading to extensions from some excellent commenters, Sol in particular.
(iii) 360's "The number 2009" post adds a different perspective to this game -- some clever identities involving sums of fractions, not to mention some demographic info about the 2009th largest city and using extrapolation to surmise the 2009th richest person in the world!
(iv) Denise has followed her "annual" tradition of a number game with the "2009 Mathematics Game," challenging her readers and students everywhere to represent as many as possible of the integers from 1 to 100 using only the digits 2, 0, 0 and 9 and standard arithmetic operations (which she clearly defines) and grouping symbols. I particularly like her use of the convention 0^0 = 1, a controversial definition to say the least. This game is addictive and will keep Denise's readers busy for the next 12 months or so!
(v) Other 2009 posts and curiosities I've omitted?? Let me know in the comments...

3. Speaking of challenges, I asked my readers to solve a silly little riddle:
"What do call solving an equation twice on Jan 1st?"
We had three "first responders" so I will close the contest down now and announce our winners in the order in which I rec'd their email solutions. By the way the answer can be found "hidden" near the top of this post! And the winners are...
SEAN HENDERSON (and his wife!)
JUSTIN TOLENTINO
ROBIN SCHWARTZ

4. Finally, I discovered by accident that MathNotations and several of the math blogs I enjoy reading are featured in a new aggregator of sorts, Alltop, All the top Math News. The developers liken it to a virtual magazine rack, in which the titles of the latest 5 posts or articles from the selected web sites are listed (you can see more detail by rolling over the titles). I am finding it useful for getting current information from some sites I had not seen before. We'll see where this goes. Ars Mathematica, Sol's Wild About Math and MathNotations are all ranked in the Top Ten whatever the significance of that ranking may be...