Answer: 511
Explanation:
53.
For this problem simply plug in the numbers: 1 through 9 for n
the n=1 on the bottom represents the start and the 9 at the top represents the end
and the 2^n-1 represents the rule
solving for a1: plugging in one for n
a1=2^1-1
a1=1
a2=2^2-1
a2=2
a3=2^3-1
a3=4
a4=2^4-1
a4=8
a5=2^5-1
a5=16
a6=2^6-1
a6=32
a7=2^7-1
a7=64
a8=2^8-1
a8=128
a9=2^9-1
a9=256
after finding all these values add them all together and you should get your answer
1+2+4+8+16+32+64+128+256
=511