Pineapple on 08 November 2013
I'm not sure where your 1.73 million is coming from. I'm getting it at 1545k for the 4 weeks. You get something very close to your number if you also add in the week ending 28th September, but that's not part of October, so I'm not sure.
I became a bit curious by this thread, so I decided to actually write down all the data.
| Week 1 | Week 2 | Week 3 | Week 4 | Week 5 | Average 4 weeks | Average 4 weeks DS + 3DS | |
| 2005 | 0 | 0 | |||||
| 2006 | 291 | 274 | 298 | 376 | 309,75 | 309,75 | |
| 2007 | 410 | 383 | 424 | 405 | 426 | 405,5 | 405,5 |
| 2008 | 350 | 359 | 363 | 382 | 630 | 363,5 | 363,5 |
| 2009 | 336 | 318 | 324 | 381 | 339,75 | 339,75 | |
| 2010 | 278 | 245 | 240 | 314 | 269,25 | 269,25 | |
| 2011 | 174 | 176 | 211 | 243 | 201 | 279 | |
| 2012 | 194 | 211 | 202 | 239 | 283 | 211,5 | 243,25 |
| 2013 | 223 | 481 | 430 | 414 | 387 | 395,25 |
As you can see, the 3DS' 4-week average is ever so slightly slightly behind 2007's 4-week average, but that difference is essentially nothing - it's less than 5%.
I put the total sales into a graph, as well. 
