Pairs, Two pairs on the flop

[FlyingStart]

I'm not really looking for a discussion here, just the plain facts

What are the probabilities of someone hitting either a pair or two pairs on the flop with eiter 2, 3 or 4 people seeing the flop, GIVEN that none of these players have pairs to begin with?

What I would like to see is a table looking something like this:

____________________ Pair Two pairs
2 Players seeing the flop a%....b%......
3 Players seeing the flop c%....d%......
4 Players seeing the flop e%....f%......