Answer:
5461
Step-by-step explanation:
You can recognize this as the sum of 7 terms of a geometric series with first term 1 and common ratio 4.
That sum is given by ...
[tex]S_n=a_1\cdot\dfrac{r^n-1}{r-1}[/tex]
where a1 is the first term and r is the common ratio.
Filling in the numbers, we have ...
[tex]S_7=1\cdot\dfrac{4^7-1}{4-1}=\dfrac{16384-1}{3}=5461[/tex]
The sum is 5461.
