10, 1,000, 100,000, 10,000,000
What power of 10 is the 80th term?
We see the following pattern
10^1 = 10
10^3 = 1000
10^5 = 100,000
10^7 = 10,000,000
f(n) = 10^(2n - 1)
We build the 80th term:
f(80) = 10^(2(80) - 1)
f(80) = 10^(160 - 1)
f(80) = 10^159