Find the 7th partial sum of summation of 6 open parentheses 3 close parentheses to the I minus 1 power from 1 to infinity

The seventh partial sum of the given expression summation of 6 (3) ^ (I-1) from 1 to infinity can be obtained using the calculator and using 7 as the upper limit. Hence, inputing in the calculator, the answer is 6558. The summation process can also be done manually to verify the answer