NB. ps. lucky might be a good candidate as example NB. for conversion to tacit form.
A bit late but I decided to give it a try:
split=: {.;}.
sieve =: [#~#@[$ 0,~<:@]$1:
lucky=: [:; [:(#@[(>:@[ split ]sieve {),)&>/^:({:&>@{.<#@;)^:_ [: split
1+2*i.
-- Met vriendelijke groet, @@i = Arie Groeneveld ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
