8n+3
8n+3. Just substitute 1, 2, 3, 4, 5 for n. So, you should get:
(8*1) + 3 = 11
(8*2) + 3 = 19
(8*3) + 3 = 27
(8*4) + 3 = 35
(8*5) + 3 = 43