John, Yes, that looks like a great approach. I was looking into #.i. 8 but had not seen the pattern you describe.
An unrelated issue has arisen for me which others may be able to address. i: 7j7 _7 _5 _3 _1 1 3 5 7 #. _1+2*#:i.8 _7 _5 _3 _1 1 3 5 7 but I cannot figure out how to produce _1+2*#:i.8 from i: 7j7 . I tried the following but don't quite get the desire result. #.^:_1 i: 7j7 0 0 1 0 1 1 1 0 1 1 1 1 0 0 1 0 1 1 1 0 1 1 1 1 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
