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All-different win totals in a 32-team round robin

Question

Thirty-two teams play a round robin, so every pair of teams meets exactly once, and each game is a fair coin flip independent of all others. The probability that no two teams finish with the same number of wins can be written a!2b\dfrac{a!}{2^b} with integers a,ba,b and bb as large as possible. Find a+ba+b.

Short answer

528528. There are (322)=496\binom{32}2=496 games. Distinct win counts must be 0,1,…,310,1,\dots,31, which forces a strict ranking where each team beats exactly those below it; each of the 32!32! orderings gives one outcome. So the probability is 32!2496\tfrac{32!}{2^{496}} and a+b=528a+b=528.

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