If you have AK the number of combos where you flop a pair (of A's or K's) or more is

6(44C2) +6c2(44) +6C3= 6(44C2)+ 15(44) +20

you can flop a flush 11C3 ways, and a flush draw (w/o a pair (of A's or K's) 10C2(27) ways.

You can flop a straight (but not a flush) 4^3-1 ways.

Finally for straight draws which aren't flush draws

a) in a paired board 6(4*6 -3) = 126 ways.

b) in a non paired board 27( 64- 1 -12)= 51*27 ways.

Now add all these up and divide by 50C3 to get your desired probablility! (and forget anything you read by the sitting bull
[img]/forums/images/icons/smile.gif[/img] ).