Missing pages!

Logic Level 2

It's a lovely evening, you are reading a newspaper in your tea time. As you go through the newspaper, you find that pages 6 and 9 are missing (your newspaper consists of 16 pages).

Considering the case above, what are the other pages which must be missing?

Details and assumptions:

If page 1 is missing it means, the whole sheet including the last page is missing.
Include pages 6 and 9 in your answer.
If you think the missing pages are: 1, 2, 3 and 4 provide the answer as $1+2+3+4+6+9=25$ .