Although you cannot adjust the official odds based on the number of players, you can adjust the estimated odds by how people have been betting. For example, let's say I'm holding 7-8 unsuited in a 6-man game and the flop is free. It's 5-6-K, no flush possibilities. You're the wheel. The betting is check, raise, fold, fold, see to you. My estimations of the hands would be:

1. Face(not King)-5/6
2. K-x
3. 10-7 (or so)
4. J-8 (or so)
5. A-x

Given that, the odds change quite a bit. Intead of 8 outs from 47 cards, it's actually 8 outs from around 39 cards. That's 20.5% (37.2% for either). Compare that to your official 17.0% (31.5% for either).

Let's change the game. You've got 9-10 suited. Intead of 5-6-K, it's 2-6-K, but the 2-6 is your suit. All other things are the same. So, we now have 9 outs in 39 cards. Your number is 19.1% (35.0%). My number is 23.1% (41.3%). If I've got a medium stack, that extra 4-6% means a lot.

The numbers are all well and good, but you can't depend on them. 6% is 1 of 16. That means, with reading the bets, you'll win an extra hand every hour. I don't know about you, but I wouldn't mind that.