define tree(x,y,z,limit){
   auto nodecount
   /* It is assumed that y<=limit and z<=limit */
   /* Return value: number of nodes in the tree */
   
   /* output this node */
   print "(",x,",",y,",",z,")\n"
   nodecount = 1

   /* do left subtree (if limit not exceeded) */
   newz1=3*x*z-y
   if ( newz1 <= limit ){
       nodecount += tree(x, z, newz1, limit)
   }
   
   /* do right subtree (if limit not exceeded) */
   newz2=3*y*z-x
   if ( newz2 <= limit ){
      nodecount += tree(y, z, newz2, limit)
   }

   return nodecount
}

/* test*limit) prints all markoff triples (x,y,z) with x<y<z and 5<=z<=limit.
 * The recursion is due to Alan Offer July 26, 2013
 */
define test(limit){
   auto counter
   counter = tree(1,2,5,limit)

   print "\nNumber of nodes is "
   return counter
}