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You mean that you want to construct every associative binary operation possible from $S\times S\rightarrow S$? – rschwieb Apr 29 '12 at 18:44
Yes :) something besides constructing them blindly and removing non-associative ones. – idonutunderstand Apr 29 '12 at 18:59
Considering how difficult it is to constructs all the groups of order, say, 2048, I'd be surprised if there were any useful procedure for constructing all the semigroups. By the way, the number of semigroups on a set of 7 elements is already 7743056064, according to – Gerry Myerson Apr 30 '12 at 3:05
We still don't know how many semigroups of order 10 there are I believe. I think $9$ was cracked a couple of years ago. – user23211 Apr 30 '12 at 12:29

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