Another reader points out the existence of Mathematica Home Edition, which I had not heard of. My prominent website might put me in the "non-profit organization" category. But we can also run Adam Goucher's examples in Wolfram Alpha, which accepts most Mathematica syntax. His first example is "LatticeReduce[{{1,0,0,100000,-100000,0},{0,1,0,0,3652421897/100,-3652421897/1000},{0,0,1,-295305890/100,0,295305890/1000}}]", here is the link: http://www.wolframalpha.com/input/?i=LatticeReduce%5B%7B%7B1%2C0%2C0%2C10000... A less precise answer, like the Metonic cycle, is obtained by changing the obvious scaling constants, giving "LatticeReduce[{{1,0,0,10000,-10000,0},{0,1,0,0,3652421897/1000,-3652421897/10000},{0,0,1,-295305890/1000,0,295305890/10000}}]" : http://www.wolframalpha.com/input/?i=LatticeReduce%5B%7B%7B1%2C0%2C0%2C10000... -- Robert Munafo -- mrob.com Follow me at: gplus.to/mrob - fb.com/mrob27 - twitter.com/mrob_27 - mrob27.wordpress.com - youtube.com/user/mrob143 - rilybot.blogspot.com