Let A = \{ 1,a_{1},a_{2},,a_{18},77 \} be a set of integers with 1 < a_{1} < a_{2} < < a_{18} < 77. Let the set + A = \{ x + y : x,y \in A\} contain exactly 39 elements. Then, the value of a_{1} + a_{2} + + a_{18} is equal to: Sequence & Series (Mathematics) | DivineJEE