Answer to Puzzle Contest:

323. To steal Kevin Lombardo's explanation:

"The answer is:

323

The numbers are products of consecutive prime numbers.

2 x 3 = 6
3 x 5 = 15
5 x 7 = 35
7 x 11 = 77
11 x 13 = 143
13 x 17 = 221
17 x 19 = 323"

And yes, 2 is a prime number, and 1 is not. Many people have that the other way around. 2 is the only even prime number.

Winner: Michelle Nichols

Contest Statistics: Newsletter sent to 297185 subscribers, 41 answers submitted, 36 answers correct, 87.80% accuracy. Chance of a correct answer winning: 2.78%.