No two card shuffles will EVER be the same.

[Shawnee123]

Originally Posted by HungLikeJesus

I forgot to check one of the boundary values. For n = 52!, P should equal one. Instead, for n = 52!, P = (52!-1)/2, so something is not right.

Then, what is this n? Does n=52 or does n=number of shuffles?

Originally Posted by HungLikeJesus

I'd better present my logic to see if anyone disagrees.

(n*(n-1))/(2*52!) = P; solve for P, where P = probability of 2 or more matching shuffled decks in n shuffles.