Find the sum of the first 14 terms of this progression, 2, 5, 8, 11,.........?
The terms will be 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41.
Adding with the sum of series formula we get:
14(2+41)/2
=14(43)/2
=301
+781 
