If we have 100 numbers 1100 then we clearly have 100 items. For every big number theres a small number on the other end. If your list represents an Arithmetic series that is the difference between the consecutive numbers is the same then use the formula.
Sum n2 a1 an where n number of numbers on the.
If the question calls. Then the next consecutive numbers would be x 1 x 2 and x 3. Set them both to 1p6 18pt. It is developed by using impeccable algorithms and has the simplest front end.