Why should order table when defining the size of the allocated space

The first sequence table structure in Python

Sequence table characteristics: 1, continuously stored in the memory; 2, elements of the same type;

Thus it can easily be determined by the respective elements of the sequence table offset (the size of the data type).

You can not specify that the capacity of the order table, the default is unlimited storage?

 If the range is not specified, may define a linked list in the end of the current address of the sequence table, the table trying to insert the next sequential element will be discontinuous.