Andrea Ambu wrote: > I wasn't able to find a good way to do it, i tried: > z=:p:i.5 > z*/z > 4 6 10 14 22 > 6 9 15 21 33 > 10 15 25 35 55 > 14 21 35 49 77 > 22 33 55 77 121 > > what I'd need from this matrix is an array containing the elements on > its high (or low) triangle, diagonal included, as the rest are > duplicated items. Any good way to do this?
Raul suggested a couple of ways to do this. Unfortunately, it will not solve the original problem, since you need too big an array. As a very mild spoiler , I suggest fixing a prime and counting the number of semiprimes in which it participates. The solution then comes down to 3 or 4 lines in J. Best wishes, John ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
