Question

what is the rule for 1=2, 2=4, 3=8?

Answer 1

when there is 1 number of positions, there is 2 number of arrangements.
when there is 2 number of positions, there is 4 number of arrangements.
when there is 3 number of positions, there is 8 number of arrangements.
when there is 4 number of positions, there is 16 number of arrangements.

Answer 2

2^1=2
2^2=4
2^3=8

Answer 3

so tell me hw fourth position is 16?