Question 511346
The sequence goes like:


1,3,5,7,9,1,3,5,7,9,...,5,7.


{1,3,5,7,9} will occur a total of 24 times, so the sum of the first 24*5 = 120 terms is 24(1+3+5+7+9) = 600. The last four terms, 1,3,5,7, have a sum of 16 so the total sum is 616.