It would have been smart of me to read the docs; I would have seen that (_4 p: *:) 2+i.10 3 7 13 23 31 47 61 79 97 113
> On Apr 10, 2021, at 15:03, 'Nollaig MacKenzie' via Chat <[email protected]> > wrote: > > Generalizing recklessly from the single example, 7 of 9, > I conjectured that > > borgnum n > > would be the greatest prime less than n^2 > > Looking for a J expression took me to: > > borgnum=:p:@(<:@(p:^:_1))@*: > > whence the 1st 10 borg numbers are > > 3 7 13 23 31 47 61 79 97 113 > > What was pleasing, of course, was the way p:^:_1 gave just what I wanted. > > I checked OEIS.org, and, indeed, the sequence is there, A053001, not, alas, > identified as the borg numbers. > > Sent using Hushmail > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
