Define the following three members of series Define the following three members of the series: 1, 2, 4, 6, 10, 12, 16, 18, 22, 28,...
I can only see that i has something to do with adding 2 but i cant get it. 

See how that sequence relates to the famous sequence $$2,3,5,7,11,13,17,19,23,29...$$ of consecutive prime numbers.
$$2,3,5,7,11,13,17,19,23,29...\\1, 2, 4, 6, 10, 12, 16, 18, 22, 28...$$
