It doesn't cap at 64? That's the perfect number for 6 rounds of Swiss.
After round 1 there are 32 1-0's and 32 0-1's
After round 2 there are 16 2-0's, 32 1-1's, and 16 0-2's
After round 3 there are 8 3-0's, 24 2-1's, 24 1-2's, and 8 0-3's
After round 4 there are 4 4-0's, 16 3-1's, 24 2-2's, 16...