paralled buddy prima

how to solve the attached problem in genetic algorithm
for association rules.
1) plz concentrate on table-1, table-2 and table-3 here we are
looking for series whose numbers are not increasing as number of items
increases (Table-2).......

2) The weakness of this representation is that the product of the
prime number is a very large
number for a transaction with more number of items.

3) may we find other series that multiplication are smaller and
unique.........OR may we divide or subtract from prime number so
that it keeps also property of prime number so that multiplication
will not increase.