Which one of the numbers does not belong in the following series?
1 - 2 - 5 - 10 - 13 - 26 - 29 - 48
1, 5, 26, 29, 48

I have never been good at these number questions and now that I'm 61 it's even harder.

The person who helped me before was great, thank you so much. I did finally get it. Sounds like I'm pretty dense, but due to some major surgeries my thinking is off.