Determine the sum of all possible n values, with n < 100 so that 2^n+1 is divisible by 3.
n = 1 , 4 , 7 , 10 , 13 , 16 , 19 , 22 , 25 , 28 , 31 , 34 , 37 , 40 , 43 , 46 , 49 , 52 , 55 , 58 , 61 , 64 , 67 , 70 , 73 , 76 , 79 , 82 , 85 , 88 , 91 , 94 , 97 , Total = 33 such numbers.
sum(1 , 4 , 7 , 10 , 13 , 16 , 19 , 22 , 25 , 28 , 31 , 34 , 37 , 40 , 43 , 46 , 49 , 52 , 55 , 58 , 61 , 64 , 67 , 70 , 73 , 76 , 79 , 82 , 85 , 88 , 91 , 94 , 97) =1,617
