Question

Cat face 2+2^2+2^3+...+2^2017?

Answer 1

$\boxed{2^1+2^2+2^3+...+2^{n} = 2^{n+1}-2} \\ \\ 2^1+2^2+2^3+...+2^{2017} = 2^{2017+1}-2 \Rightarrow \\ \\ \Rightarrow 2^1+2^2+2^3+...+2^{2017} = 2^{2018}-2$