Little Strong's Ancestors

Little Strong's Ancestors
Little Strong encountered a perplexing question that left him puzzled:

He has two parents,
And each of his parents also has two parents.

Therefore, Little Strong has a total of four grandparents (2 × 2 = 22 = 4).

Similarly, he would have eight great-grandparents (23 = 8).

By extrapolation, going back n generations, Little Strong's ancestors would total 2n individuals.

Assuming a generation is 30 years, 600 years ago, which is 20 generations back, Little Strong's grandparents would number over one million (220 = 1,040,400).

So, 1,500 years ago, which is 50 generations back, wouldn't Little Strong's ancestors be in the trillions?

(250 = 1,126,000,000,000,000)