The same reasoning used for the original problem applies more generally. The probability that gcd(i[1],...,i[n]) = gcd(j[1],...,j[n]) is zeta(2n)/zeta(n)^2. It seems strange that for n even the answer is rational, while for n odd the result is of unknown character, presumably transcendental. Gene ____________________________________________________________________________________ Need a quick answer? Get one in minutes from people who know. Ask your question on www.Answers.yahoo.com