1. n+1=ab ;for some a,b in N that are less than n+1
Since n! is the product of all natural number from n down to 1, a and b which are less than n+1 must be somewhere in 1,2,...,n. Thus, the product ab=n+1 must divide n!
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Mathematics, rightly viewed possesses not only truth, but supreme beauty. B.R.
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