3n + 2 when n = 1 = 3 + 2 = 5
when n = 2 we have the 2nd term which is 3(2) + 2 = 8
for n = 3 we have 3rd term = 11 and so on
This is an arithmetic series with first term a1 = 5 and common difference = 3
so Sn = (n/2) ( 2a1 + (n - 1)d))
there fore Sum of 14 terms = (14/2)(2*5 + 13*3)
= 7 * 49 = 343 answer
