I am getting (n+1)! - 1 but I do not know of a proof of that.
]]>http://www.mathisfunforum.com/profile.php?id=337902012-12-10T20:46:45Zhttp://www.mathisfunforum.com/viewtopic.php?pid=243401#p243401Consider all non empty subsets of the set .
For every subset we find the product of each of these elements.