Help on a series

[johnhany97]

6 8 11 15 16 21 22 26 29 31

I am trying to solve this series.. Supposedly the user inputs n required number of digits and the program outputs the relevant number of digits from the series.

The thing is I can't see a series between the numbers.. I thought they might be like multiples of some number or something like that but I couldn't figure it out.. could someone help?

Thanks in advance