The clues of the December 2013 Listener crossword consist of formulae in eight unknowns, all of which are two-digit prime numbers. The sum of all eight unknowns is given to be 600. The first task, therefore, is to find the possible sets of answers...
This code is based on my initial Scheme version, which may be found at https://github.com/pozorvlak/warmup/blob/master/listener2/candidates.rkt .
The prime sieve code is originally by Rob Pike, and taken from http://golang.org/doc/play/sieve.go .