Now we define an ordering of the k-tuples of natural numbers as follows: should hold if either , or , and precedes in lexicographic order. [Here denotes the sum of the terms of the tuple.] Denote the nth tuple in this order by .
Now we define an ordering of the k-tuples of natural numbers as follows: should hold if either  or , and precedes in lexicographic order [Here denotes the sum of the terms of the tuple.] Denote the nth tuple in this order by .