The output files from cramer4.c are

ordered4tuples --- contains 4-tuples in the form a0 <= a1 <= a2 <= a3,
                   but there may be repetition.  This file is further
                   processed by "lexicographic4.c"

series --- Contains the 4-tuples that fall into infinite series,
           arising from the case when det C does not depend on 
           m0.  (There can be overlap with other files.  The same
           4-tuple can appear in several ways, once in a series
           or on its own).

multiples --- also comes from the case where det C does not depend
           on m0.  Here we don't get a series because the shift
           vector is a multiple of [a1,a2,a3] and therefore most
           4-tuples in this would-be series violate the relatively
           prime condition.  There is nothing new here --- all are
           found in final4tuples already.

zerozero --- output from cramer4.c  in the case where d0/detC can
             be made 0/0 by a careful choice of m0.  This file is
             always empty.