daily riddle #27

Words
38
Reading
1 min
8y
Listen to this post
~1 min

New week, new riddle. The fomular behind the following number row is well known. But I changed the beginning a little bit, so it's slightly diffucult. But overall it should be pretty easy.

3 | 4 | 7 | 11 | 18 | ?

daily riddle #27 | Ecency